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Performance and Mechanism of Aqueous Arsenic Removal with Nanoscale Zero-Valent Iron

Meirong Li , Chenliu Tang , Weixian Zhang , Lan Ling

Progress in Chemistry ›› 2022, Vol. 34 ›› Issue (4) : 846 -856.

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Progress in Chemistry ›› 2022, Vol. 34 ›› Issue (4) : 846-856 DOI: 10.7536/PC210445
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Performance and Mechanism of Aqueous Arsenic Removal with Nanoscale Zero-Valent Iron
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Abstract

Over 100 million people around the world are at the risk of the drinking arsenic-contaminated water. It is urgent to solve this severe security issue of drinking water caused by arsenic which is highly toxic and difficult to dispose of. Nanoscale zero-valent iron (nZVI) is one of the most extensively applied nanomaterials due to its efficient removal of pollutants such as, heavy metals, nitrates, phosphates, perchlorates, halides, polycyclic aromatic hydrocarbons and phenols. nZVI-based remediation has grown into a prominent sub-field of environmental nanotechnology, with nearly 60 in-situ remediation projects, pilot and full-scale wastewater treatment projects conducted worldwide. Its unique core-shell structure and surface properties enable nZVI to remove arsenic efficiently through adsorption, co-precipitation and reduction process. Herein, the latest progress of nZVI and various nZVI-based materials for arsenic contaminated water remediation is reviewed. The removal behavior and its influence by initial solution pH, contact time, dosage of nZVI, arsenic initial concentration, coexisting ions and organic matters are presented, with special emphasis on the removal mechanism. The iron oxide/hydroxide on the surface of nZVI rapidly adsorbs the arsenic in the solution and transforms to arsenic-iron co-precipitation. If the As solution is deoxygenated, reduction of As(Ⅲ) and As(Ⅴ) to As(0) occur during the adsorbed arsenic diffuse into the iron oxide. In addition, the research progress of four kinds of nZVI-based materials for arsenic removal are summarized, including nZVI supported with porous materials, rare metals loaded nZVI, nZVI surface modified with stabilizer and green synthesis nZVI. Finally, possible improvement of remediating arsenic contaminated water with nZVI and nZVI-based materials are also proposed.

Contents

1 Introduction

2 Aqueous arsenic removal with nanoscale zero-valent iron

2.1 Nanoscale zero-valent iron

2.2 Removal mechanism of aqueous arsenic with nZVI

2.3 Influencing factors of removal efficiency

3 Aqueous arsenic removal with nZVI-based materials

3.1 nZVI supported with porous materials

3.2 Metal loaded nZVI

3.3 Surface stabilizers modified nZVI

3.4 Green synthesis nZVI

4 Conclusion and outlook

Graphical abstract

Keywords

arsenic / nanoscale zero-valent iron / nZVI-based materials / removal mechanism / removal efficiency

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Meirong Li, Chenliu Tang, Weixian Zhang, Lan Ling. Performance and Mechanism of Aqueous Arsenic Removal with Nanoscale Zero-Valent Iron. Progress in Chemistry, 2022, 34(4): 846-856 DOI:10.7536/PC210445

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1 Introduction

In recent decades, arsenic poisoning incidents have occurred frequently at home and abroad, and arsenic pollution has become a serious environmental problem faced by developing countries, including China[1]. Natural causes such as volcanic eruptions and rock weathering may cause arsenic pollution. However, arsenic pollution mainly comes from human production activities such as the use of pesticides and herbicides in agricultural production, chemical production, mining and metal smelting. A large amount of arsenic is released into the environment, polluting groundwater, surface water, atmosphere and soil. In China, arsenic pollution areas are mainly distributed in Inner Mongolia, Shanxi, Tibet and other provinces (Fig. 1). From 2001 to 2005, the Ministry of Health of China carried out a national arsenic pollution survey, and 445,000 wells were investigated for arsenic pollution. The survey results showed that about 5% of the wells had arsenic concentrations higher than 50 μg/L. It is estimated that 5.6 million people in China are exposed to high arsenic concentrations (> 50 μg/L) and 14.7 million people are exposed to arsenic concentrations above 10 μg/L[2].
Arsenic, which is between metal and nonmetal in the periodic table of elements, is a group Va element in the fourth period, with an atomic number of 33 and a relative atomic mass of 74.92. It belongs to metalloid and has the properties of both metal and nonmetal. Arsenic compounds can be divided into inorganic arsenic and organic arsenic. In the natural environment, inorganic arsenic is more common, with multiple valence States of -3, 0, + 3 and + 5. The toxicity of inorganic arsenic is stronger than that of organic arsenic, and the toxicity of trivalent arsenic is the strongest in inorganic arsenic. In the water environment rich in dissolved oxygen, arsenic mainly exists in the form of arsenate, including H3AsO4, H2AsO4-, HAsO42- and AsO33-. In anoxic environment, arsenic mainly exists in the form of H3AsO3, H2AsO3-, HAsO32-, AsO43- arsenite[3].
Arsenic is toxic and carcinogenic, which threatens the health of animals, plants and human beings after ingestion. Long-term exposure to arsenic can cause serious harm to human body, such as skin cancer, lung cancer, cardiovascular disease and nervous system disease[4]. Therefore, the World Health Organization and many countries have formulated strict control standards for arsenic and its compounds: the World Health Organization recommends that the concentration of arsenic in public drinking water should not exceed 10.0 μg/L; China stipulates in GB 8978-1996 Integrated Wastewater Discharge Standard that the maximum allowable discharge concentration of total arsenic is 0.5 mg/L; According to GB 5479-2006 Sanitary Standard for Drinking Water, the limit of arsenic in drinking water is 10. 0 μg/L. In July 2019, the Ministry of Ecology and Environment of China listed arsenic and arsenic compounds in the List of Toxic and Harmful Water Pollutants, aiming to control the concentration of arsenic in water, reduce its harm to the water environment, and prevent the adverse effects of arsenic pollution on human health.
The treatment methods of arsenic-containing wastewater mainly include adsorption, coagulation, ion exchange, membrane separation and so on, but these methods have some shortcomings, such as low efficiency, high cost, and can not remove multiple pollutants at the same time[5][6][7][8][9]. For example, the coagulation sedimentation method is not suitable for the treatment of low-concentration sewage, and a large amount of coagulant needs to be added to form a large amount of arsenic-containing sludge after the reaction, which makes the subsequent treatment difficult[10]. Microfiltration membrane and ultrafiltration membrane in membrane separation method can only remove arsenic-containing particles in water, and dissolved arsenic removal requires nanofiltration membrane or reverse osmosis membrane, which has high energy consumption and high price[11]. For soil, groundwater and surface water systems, it is difficult to achieve in-situ treatment because of the large volume of the treated object and the low concentration of arsenic. Therefore, researchers are committed to exploring an efficient and economical in-situ arsenic treatment technology.
Iron is widely distributed in the earth's crust, and nZVI with core-shell structure has become one of the most efficient materials for pollutant removal because of its large specific surface area, strong reactivity and high pollution control efficiency[12,13]. And the nZVI has magnetism, so that the treated water body can be quickly separated from the material through the magnetic separation technology. In the past 20 years, several cases of water body remediation using nZVI have been carried out in the environmental field[15]. As of 2011, 58 nZVI groundwater remediation cases have been completed or are being implemented worldwide, and these remediation mainly focus on the removal of chlorinated organic pollutants[14]. There are also some practical application cases of nZVI used to treat heavy metal industrial wastewater and arsenic-containing wastewater. The nZVI continuous wastewater treatment reactor was constructed to fully recycle the nZVI in the reactor. Under the conditions of 400 L/H of influent water and 2.1 kg/m3 of nZVI dosage, the concentrations of arsenic and copper were reduced from 520 mg/L and 67 mg/L to 10 mg/L and 0.1 mg/L, respectively, to achieve efficient wastewater treatment[14].
So far, there are many research papers on the removal of arsenic in water by using nZVI and modified nZVI materials, but there is still a lack of summary work. In this paper, the mechanism of arsenic removal by nZVI and its modified materials was systematically reviewed, and the removal effects of different materials were summarized and compared, which provided support for the future development of arsenic removal by nZVI and its modified materials.

2 Removal of Arsenic from Water by Nanoscale Zero-valent Iron

2.1 Nanoscale zero-valent iron

The nZVI has large specific surface area, strong reactivity and strong reducibility, and the standard redox potential E0(Fe2+/Fe0) is about-0. 440 V. These characteristics make nZVI more advantageous in the field of environmental remediation, such as heavy metal removal, dye degradation, etc[16][17][18]. In the liquid-phase oxygen-containing system, nZVI undergoes a Fenton-like reaction (equations (1) – (6)), which promotes the oxidation of Fe (0) and the formation of an iron oxide shell, resulting in the formation of OH- and an increase in the pH value of the system[19,20].
The synthesis methods of nZVI include mechanical ball milling, liquid phase reduction, gas phase reduction, electrochemical deposition, carbothermal reduction, etc[21][22][23][24][25]. At present, the commonly used method for nZVI synthesis in the laboratory is the liquid phase reduction method, in which sodium borohydride is used as a reducing agent to reduce Fe (Ⅲ)/Fe (Ⅱ) in the solution to nanoscale Fe (0), and the commonly used iron sources are ferric chloride (FeCl3) and ferrous sulfate (FeSO4)[26]. The nZVI synthesized by liquid phase reduction method is mostly spherical particles with particle size distribution between 20. 0 nm and 100. 0 nm, and is agglomerated into chains under the action of magnetic and electrostatic forces[27]. In addition, nZVI has a core-shell structure, with a metal core of Fe (0) in the interior and an iron oxide shell on the surface. The shell is formed by the natural oxidation of Fe (0) in the medium at the moment after the formation of the core of iron (0), with an average thickness of 2. 0-4. 0 nm[28]. The iron oxide layer is composed of mixed divalent/trivalent iron oxides near the Fe (0) core and trivalent iron oxides near the water interface. After contact with water, the surface of iron oxides is covered by hydroxyl groups, forming amorphous iron oxyhydroxide (FeOOH)[29,30][31]. This special core-shell structure makes nZVI not only have the reducibility of Fe (0), but also have the adsorption properties of iron oxides[27,32]. However, the liquid phase reduction method is not suitable for large-scale industrial production because of its high cost. The gas-phase reduction method is to evaporate the solid iron salt in a vacuum environment and reduce it with H2 or CO at high temperature[23]. The electrochemical deposition method is to electrolyze the iron salt solution under the applied voltage, so that nZVI is formed on the surface of the cathode[24]. Carbothermal reduction method refers to the reduction of nanoscale iron oxides by inorganic carbon at high temperature[25]. Considering the cost and safety of preparation, electrochemical deposition and carbothermal reduction are more suitable for industrial large-scale production of nZVI[33,34].

2.2 Reaction Mechanism of Arsenic Removal by Nanoscale Zero-valent Iron

2.2.1 Reaction mechanism under aerobic condition

Under aerobic conditions, nZVI removes arsenic mainly through the synergistic effect of adsorption and co-precipitation. Kanel et al. Used nZVI (1.0 G/L) to remove As (Ⅲ) (1.0 mg/L) and As (Ⅴ) (1.0 mg/L) from water, and found that the removal rates were both above 90.0% after 10 min, and the maximum adsorption capacity of nZVI for As (Ⅲ) was 3.5 mg/G[35][36].
In the liquid phase oxygen-containing system, the Fenton-like reaction (formulas (1) ~ (6)) of nZVI promotes the oxidation of Fe (0) and the formation of iron oxide shell[19,20]. Iron oxides adsorb As (Ⅲ) and As (Ⅴ) in water to the surface of particles to form inner-sphere complexes, but different amounts of arsenic adsorption will lead to the formation of different types of complexes (monodentate complexes or bidentate complexes), and the binding energy of Fe-As bond in monodentate complexes is smaller, which is easier to desorb than bidendate complexes[37][38][38,39][40].
nZVI can remove As (Ⅲ) and As (Ⅴ) from water at a relatively fast rate, which is due to the formation of arsenic-iron coprecipitation in addition to adsorption[35]. nZVI is oxidized with water and oxygen in the presence of oxygen (formulas (7) ~ (9)), and further converted into iron oxides/hydroxides such As magnetite, hematite and goethite. During the formation of iron oxides/hydroxides, co-precipitation reactions occur with As (III) and As (V) in water, forming Fe-As oxides/hydroxide to fix arsenic in the structure[39][41][42,43].
When nZVI removes As (Ⅲ) from water under aerobic conditions, the active oxides produced by Fenton-like reaction, such As hydroxyl radical (· OH) and superoxide radical ( O 2 · -), will oxidize As (Ⅲ) to As (Ⅴ)[35].
F e 0 + O 2 + 2 H 2 O → F e 2 + + H 2 O 2 + 2 O H -
F e 0 + H 2 O 2 → F e 2 + + 2 O H -
F e 2 + + H 2 O 2 → F e 3 + + O H - + · O H
F e 2 + + · O H → F e 3 + + O H -
F e 2 + + O 2 → F e 3 + + · O 2 -
F e 2 + + · O 2 - + 2 H 2 O → F e 3 + + H 2 O 2 + 2 O H -
F e 0 + 2 H 2 O → F e 2 + + H 2 ↑ + 2 O H -
4 F e 2 + + 4 H 2 O + O 2 → 4 F e 3 + + 2 H 2 O + 4 O H -
2 F e 2 + + 2 H 2 O → 2 F e 3 + + H 2 ↑ + 2 O H -

2.2.2 Reaction mechanism under anaerobic condition

In the absence of oxygen, the mechanism of nZVI and As is not only adsorption and coprecipitation, but also reduction, As shown in Figure 2a-d. Yan et al. Used nZVI (5 G/L) to remove As (Ⅲ) (100 mg/L) under anaerobic conditions, and the removal rate reached 99.9% in 10 min[44].
In the absence of oxygen, nZVI still reacts with water (formula (7), (9)), and the pH value of the system increases to form iron oxide/hydroxide, which is conducive to the adsorption of As (III) and As (V) in the solution; The OH- and Fe (Ⅱ)/Fe (Ⅲ) released in the reaction with water were coprecipitated with arsenic. In this process, As was transferred from the ion in the liquid phase to the solid phase. The reaction occurred quickly and lasted for a short time. The reaction mechanism of this part was similar to that of the aerobic system[27,44][44].
In addition to this, there are oxidation and reduction reactions of arsenic. Zhang et al. Characterized the nZVI reacted with As (Ⅲ) and As (Ⅴ) by high-resolution X-ray photoelectron spectroscopy (HR-XPS), and the results showed that As (0), As (Ⅲ) and As (Ⅴ) accounted for 35.0%, 51.0%, 14.0% and 13.0%, 11.0%, 76.0% of the total arsenic, respectively[45]. In the reaction system of nZVI and As (Ⅲ), As (Ⅴ) is produced by the oxidation of As (Ⅲ). In the absence of oxygen, although the Fenton-like reaction is inhibited, nZVI can still react with water and oxidize to iron oxides/hydroxides, such As magnetite, hematite, goethite and ferrihydrite. The iron oxides/hydroxides produced have certain oxidizability and can oxidize As (III)[44][46,47]. As (0) is the reduction product of As (Ⅲ) and As (Ⅴ). The shell on the surface of nZVI is thin and disordered, and electrons can pass through the shell through defects. As (Ⅲ) and As (Ⅴ) adsorbed on the surface of nZVI enter the shell through diffusion and coprecipitation, and are slowly reduced to As (0)[18,48][39,49]. In addition to Fe (0), the H2 produced during the oxidation of Fe (0) and Fe (II) (formula (7), (9)) can also be used As a reducing agent to reduce As (III) and As (V) to As (0)[47].
The removal of As (Ⅲ) and As (Ⅴ) by nZVI in the absence of oxygen has been studied in depth, and the mechanism of As removal and As valence conversion has been further confirmed by other characterization methods. Yan et al. Characterized the nZVI reacted with As (Ⅲ) by XPS, and judged the distribution of As in the XPS detection depth range (~ 10.0 nm) according to the value of As 2p3/2/As 3d[44,50]. As shown in Fig. 2e, As (Ⅴ) is adsorbed on the surface of the oxide shell in contact with the liquid phase; As (Ⅲ) is uniformly distributed in the oxide shell. As (0) accumulates between the zero-valent iron and the oxidation shell, which indicates that the oxidation and reduction processes of As (Ⅲ) are dominated by the oxidation shell and the Fe (0) core, respectively. Ling et al. Analyzed the nZVI reacted with As (Ⅴ) by Cs-STEM combined with EDX, and obtained the element distribution information of arsenic, iron and oxygen, As shown in Figure 3A[31,51]. A shell with a thickness of about 1.2 nm is formed between the iron oxide shell and the Fe metal core, and the distribution of As element is larger than that of O element. The outermost As element is adsorbed on the surface of nZVI and forms a complex with the iron oxide, and the new shell inside is formed by the accumulation of As reduction products on the surface of the inner core of nZVI, which is basically consistent with the results of Yan et al. Ling et al. Used a transmission electron microscope to tilt the sample several times to collect images, and constructed a three-dimensional model of the product of the reaction between nZVI and As through software processing (Fig. 3B), and found that there was an arsenic layer with a thickness of 23.0 ± 3.00 Å between the iron oxide shell and Fe (0), which further verified the view proposed by Yan et al. That nZVI could reduce As (Ⅲ) to As (0) under oxygen-free conditions[28].

2.3 Influencing factors of removal efficiency

2.3.1 Initial pH

The removal capacity of nZVI for As (Ⅲ) and As (Ⅴ) was greatly affected by the initial pH value of the solution. Because the initial concentration of As and the dosage of nZVI were different in different experiments, the optimum pH range of nZIV for As removal was not completely consistent, but the general trend was the same.
The removal capacity of nZVI for As (Ⅲ) is stronger under weak acid, neutral and weak alkali conditions (pH 4.0 ~ 9.0). Kanel et al. Showed that the removal rate of nZVI (1.0 G/L) for As (Ⅲ) (1.0 mg/L) is higher than 88.0% at pH 4.0 ~ 10.0, but when pH is less than 4.0 or greater than 10.0, the removal rate of As (III) decreases rapidly[35]. Xia et al. Found that the removal rate of As (Ⅲ) (99.6 mg/L) by nZVI (0.5 G/L) remained above 99.0% at pH 3.0 ~ 9.0, and the removal rate decreased rapidly when pH was less than 3.0 or greater than 9.0[39]. The removal rate of As (Ⅴ) by nZVI was higher under acidic and neutral conditions (pH 3.0 ~ 7.0). Kanel et al. Found that the removal rate of As (Ⅴ) (1.0 mg/L) by nZVI (0.1 G/L) reached 100.0% at pH 3.0 ~ 7.0, and the removal rate decreased with the increase of pH[26]. Xia et al showed that the removal rate of As (Ⅴ) (99.6 mg/L) by nZVI (0.5 G/L) was higher than 90.0% at pH 3.0 ~ 6.0, and showed a downward trend at pH less than 3.0 or greater than 6.0[39].
The removal of As (Ⅲ) and As (Ⅴ) by nZVI is greatly affected by pH, which is caused by the surface charging properties of nZVI, the existing forms of As (Ⅲ) and As (Ⅴ), and the corrosion products of nZVI in different pH environments. The isoelectric point of nZVI is about 8.1. When pH < 8.1, the surface of nZVI is positively charged. At pH > 8.1, the surface of nZVI is negatively charged[27]. Fig. 4 is the Eh-pH phase diagram of As (Ⅲ) and As (Ⅴ). As (Ⅴ) mainly exists in the form of H2AsO4- and HAsO42- at pH 2.0 ~ 12.0, so the adsorption of nZVI on As (Ⅴ ′) is enhanced by electrostatic interaction under neutral or acidic conditions[52⇓~54]. When pH < 9.2, As (Ⅲ) mainly exists in the form of H3AsO3; When pH > 9.2, nZVI mainly exists in the form of H2AsO3-, and the surface of nZVI is negatively charged, so the electrostatic effect hinders the adsorption[35,52,53]. Moreover, nZVI produces different corrosion products in different pH environments, and the difference of adsorption performance of different iron oxides on As will also lead to the difference of removal effect of nZVI on As[54]. The results showed that the lepidocrocite produced by nZVI oxidation decreased when the initial concentration of the solution increased from 4.0 to 10.0. However, the production of maghemite and hematite increases, and under the same conditions, magnetite/maghemite has stronger adsorption for As than lepidocrocite[54,55]. Therefore, when the pH is slightly alkaline, the change of corrosion products is the factor that promotes the adsorption of As; However, the surface charge of nZVI and the existing form of As are not conducive to the adsorption of As, which together lead to the unsatisfactory removal effect of nZVI on As under alkaline conditions.

2.3.2 Reaction time

In the initial stage of the reaction between nZVI and As, the active sites are sufficient and the reaction rate is fast. As the reaction proceeds, the number of active sites decreases, and the reaction rate gradually decreases to reach equilibrium. The removal capacity of nZVI for As (Ⅲ) is stronger than that for As (Ⅴ), and the removal rate of As (Ⅲ) is higher than that of As (Ⅴ) in a short time at the beginning of the reaction. After a period of time, the reaction rate slows down and the reaction gradually reaches equilibrium, and the removal rates of the two are close[39].
In addition, the valence state of As is also affected by the reaction time if the reaction is carried out in the absence of oxygen. Yan et al. Analyzed the products of nZVI (5.0 G/L) and As (Ⅲ) (100.0 mg/L) in different reaction time (10 min ~ 146 d) under anaerobic conditions by XPS, and studied the change of As valence state on the surface of nZVI. At 10 min, the content of As (Ⅴ) accounted for 40.0% of the total arsenic, and As (0) accounted for about 15.0% of the total arsenic[44]. After 24 H, the proportion of As (0) gradually increased to 35. 0%. During the continuous reaction of 146 days, the content of As (Ⅴ) increased rapidly in the first 10 minutes and then decreased gradually. As the content of As (0) increases gradually, the oxidation reaction of arsenic is faster, while the reduction reaction is a relatively slow process.

2.3.3 Dosage of nZVI

The removal of As (Ⅲ) and As (Ⅴ) by nZVI followed pseudo-first-order kinetics[35,36]. The higher the dosage of nZVI, the more the active adsorption sites, and the higher the adsorption efficiency of As (Ⅲ) and As (Ⅴ). It is necessary to determine the optimal dosage according to the specific situation to achieve the maximum removal rate at the minimum dosage of nZVI.
When nZVI reacts with As (Ⅲ) in the absence of oxygen, the valence state of arsenic is affected by the dosage of nZVI. With the increase of the dosage of nZVI, As (Ⅲ)/As (Ⅴ) in the system is more easily reduced to As (0). Yan et al. Used XPS to analyze the As valence state on the surface of nZVI after the reaction of nZVI (0. 4, 1. 0 and 5. 0 G/L) with As (Ⅲ) (100. 0 mg/L), and found that the formation of As (0) was detected when the dosage was 5. 0 G/L, but not when the dosage was low[44]. When the dosage of nZVI is low, the oxidation of nZVI is more serious, and the content of Fe (0) and other reducing substances decreases, which is not conducive to the reduction of As.

2.3.4 As initial concentration

The higher the initial concentration of As, the longer the time for the reaction to reach equilibrium, and the adsorption capacity of nZVI for As increases, but the reaction rate decreases. When the adsorption capacity of nZVI for As reaches the maximum adsorption capacity, the reaction reaches equilibrium, and the adsorption capacity of As does not increase even if the initial concentration is increased.
In addition, due to the hydrolysis of arsenate, the higher the initial concentration of As, the higher the initial pH of the solution, so after the addition of nZVI, the formation of iron oxides/hydroxides is also more, resulting in the weakening of the reducibility of nZVI and the valence state of arsenic is affected[45]. When the initial concentration of As (Ⅲ) is low, nZVI shows stronger reduction characteristics, and the proportion of As (0) produced by reduction to total arsenic is higher. However, the proportion of As (Ⅴ) is not significantly different, indicating that the oxidation of As (Ⅲ) is not significantly affected by the initial concentration of As[44].

2.3.5 Coexisting ions and organic matter

The effects of different coexisting ions on the removal of As (Ⅲ) and As (Ⅴ) by nZVI are different at different ionic strengths. Kanel et al. Found that HCO3-, SO 4 2 -, NO 3 -, H4SiO4, and PO 4 3 - at the same concentration (1.0 mM) were added to the reaction system.H4SiO4 and PO 4 3 - have great influence on the removal rate, while HCO 3 -, SO 4 2 - and NO 3 - have little influence on the removal rate[35,36]. However, too high concentration (10.0 mM) of HCO 3 -, SO 4 2 - and NO 3 - coexisting ions can also lead to a significant decrease in the removal rate, and the decrease is smaller than that of H4SiO4 and PO 4 3 -. The competitive effect caused by the existence of coexisting ions affects the adsorption effect of As, the effect of low-valent anions on the system is small, and the effect of competitive adsorption caused by the existence of multi-valent anions on the removal rate is obvious[56⇓~58].
The presence of organic matter also affects the removal of As by nZVI. Morgada et al. Added 2 mg/L humic acid (HA) to nZVI to remove As (Ⅴ), the removal rate was reduced by 50%, and the removal rate was also affected and reduced[59]. Giasuddin et al. Found that the addition of 20 mg/L HA reduced the surface normalized rate constants (Ksa) of As (Ⅲ) and As (Ⅴ) removal by nZVI by 43% and 68%, respectively, and the removal rates were also reduced from about 90% to about 60%[60].

3 Removal of Arsenic from Water by Modified Nanoscale Zero-valent Iron

nZVI has limitations in in-situ remediation, transportation and storage, which are mainly reflected in the following two aspects: (1) nZVI particles are prone to agglomeration: nZVI particles are small in size and large in specific surface area, and magnetic and electrostatic forces work together to make nZVI very easy to agglomerate. Especially in natural water system, the ionic strength is higher, the aggregation of nZVI is more serious, and the activity and mobility are reduced[61,62]. (2) nZVI is easily oxidized: nZVI has high reactivity and unstable chemical properties, and is easy to react with environmental media (such as oxygen and water)[19,63]. Researchers have improved the above problems by modifying nZVI. Common modification methods include loading nZVI on porous materials, metal doping nZVI, adding stabilizer coating on the surface of nZIV, and green synthesis of nZVI, as shown in Figure 5.

3.1 Porous material supported modified nanoscale zero-valent iron

In recent years, loading nZVI on porous materials such as activated carbon, montmorillonite and reduced graphene oxide has become one of the more common modification methods of nanoscale zero-valent iron[64][65][66][67]. Porous material-supported nZVI is usually synthesized by impregnation method. The supported material is immersed in ferrous salt solution or ferric salt solution for several hours, and then sodium borohydride is added for reduction. The nano-zero-valent iron particles generated by reduction are uniformly dispersed on the porous material, as shown in Figure 6a-d[66,68].
The particle size of nZVI is small, so it is difficult to fix it on the bed column, and it is easy to run off in water treatment, resulting in iron pollution[69]. The carrier can provide stable sites for nZVI, and the particle size of the loaded modified material is large, so that the modified material can be set as a fixed bed for water treatment. Under the support of the porous material, the aggregation of nZVI is inhibited, the nZVI is dispersed on the surface of the porous material, the specific surface area is increased, and the active sites for adsorbing pollutants are increased, so that the interaction activity of nZVI with various heavy metal ions is improved[70⇓~72]. Moreover, many materials have adsorption to arsenic, which can further improve the removal capacity of materials to arsenic.
The adsorption effect of As (Ⅲ) and As (Ⅴ) was improved by loading nano-iron on porous materials. The maximum adsorption capacity of montmorillonite supported nanoscale zero-valent iron (Mt-nZVI) prepared by Bhowmick et al. For As (Ⅲ) and As (Ⅴ) was 59.9 and 45.5 mg/G, respectively; Zhu et al. Obtained activated carbon supported nanoscale zero-valent iron (nZVI/AC) for removing As in drinking water by impregnation method, and the iron loading was about 8.2 wt%.The maximum adsorption capacities of nZVI/AC for As (Ⅲ) and As (Ⅴ) were 18.2 and 12.0 mg/G, respectively; Wang et al. Showed that the maximum adsorption capacities of reduced graphene-supported nanoscale zero-valent iron (nZVI/rGOs) for As (Ⅲ) and As (Ⅴ) were 35.8 and 29.0 mg/G, respectively; the maximum adsorption capacity of nanoscale zero-valent iron/phosphotungstic acid/graphene-like nitrogen carbide composite (Fe0@PTA/g-C3N4) synthesized by Chen et al. For As (Ⅵ) was[65][69][73][74].
The reaction kinetics showed that the adsorption efficiency of As (Ⅲ) and As (Ⅴ) on the porous material loaded with nZVI was high at the initial stage, and then gradually slowed down until the reaction reached equilibrium. In the initial stage of the reaction, As (Ⅲ) and As (Ⅴ) are mainly adsorbed on the surface of the material or on the nZVI in the larger pores, so the reaction is rapid. As the reaction goes on, the adsorption of nZVI in the outer and large pores gradually reaches saturation, and As (Ⅲ) and As (Ⅴ) need to diffuse into the mesopores or micropores to be adsorbed, and with the decrease of arsenic concentration, the diffusion rate decreases, so the rate decreases significantly and gradually reaches equilibrium[65,69,73].

3.2 Metal-doped modified nanoscale zero-valent iron

nZVI is modified based on surface doping with metals such as Pd, Pt, Ni, Ag, and Cu, as shown in Fig. 6e – G[75].
The bimetallic primary cell promotes electron transfer in the system, and the doped metal has a catalytic effect, which can effectively improve the dechlorination and hydrogenation reaction efficiency of halides[76⇓~78]. In recent years, nZVI modified by metal doping has also been applied to the removal of arsenic from water. After doping with noble metals, Fe (0) is oxidized more rapidly, and the release of hydroxyl is accelerated (formula (1), (7)), which promotes the formation of iron oxides on the surface, facilitates the adsorption of As (III) and As (V), and generates arsenic-iron coprecipitation, thus improving the removal efficiency[79].
Sep Sepúlveda et al. Considered that the adsorption of As (Ⅲ) and As (Ⅴ) by Cu-nZVI followed the Freundlich model[80]. However, Babaee et al. Considered that it conformed to the Langmuir model, and calculated that the maximum adsorption capacity of As (Ⅲ) and As (Ⅴ) was 19. 7 and 21. 3 mg/G, respectively, which had the prospect of being applied to groundwater treatment[79]. When the isoelectric point of Cu-nZVI nanoparticles is 8.0 ~ 9.0 and pH is 4.0 ~ 8.0, the removal rate of As (Ⅴ) is higher than 90.0%, and when pH > 8.0, the removal rate decreases. The removal of As (Ⅲ) was stable at pH 4. 0 ~ 7.0, and the removal efficiency began to decrease at pH > 7.0[79].

3.3 Surface stabilizer modified nanoscale zero-valent iron

Stabilizers such as polyvinyl alcohol (PVA) and polyacrylic acid (PAA) are added during the synthesis of nZVI to alleviate the agglomeration of nZVI, obtain nZVI with more stable chemical properties, and control the particle size, as shown in Figure 6h[81][82][83][81]. The synthesis of nZVI modified by surface stabilizer is usually carried out by introducing the stabilizer before the reduction of Fe (Ⅱ)/Fe (Ⅲ) by sodium borohydride.
After the introduction of stabilizer, the agglomeration of nZVI is alleviated, the specific surface area is increased, and the adsorption sites are increased. At the same time, oxygen-containing functional groups, such as carbonyl, carboxyl and hydroxyl, which can form complexes with heavy metal ions, are added to the surface of nZVI, so the modified nZVI has better affinity for heavy metals in water[61][84].
Azzam et al. Used EDTA modified nZVI to treat As-containing wastewater, and the material achieved good controlled synthesis. The removal effect of As (Ⅴ) was the best at pH 7.0, the removal rate reached 99.7%, and the maximum adsorption capacity was 306.7 mg/G. Moreover, the modified nZVI was affected by different concentrations (10.0,20.0,50.0,100.0,200.0,300.0 mg/L) of coexisting cations Na+, K+, Ca2+,Mg2+ and anions Cl-, PO 4 3 -, NO 3 -, SO 4 2 - have little effect[85]. Kim et al. Used SDS-nZVI synthesized by sodium dodecyl sulfate wrapped nZVI to treat arsenic in tailings, and the concentration of arsenic in effluent decreased significantly[86].

3.4 Green synthesis of nanoscale zero-valent iron

The synthesis of nZVI by traditional sodium borohydride reduction of Fe (Ⅱ) and Fe (Ⅲ) salts has some shortcomings, which limits the wide application of nZVI. First of all, sodium borohydride is toxic and dangerous chemicals, which are prone to accidents during storage, transportation and use[87]. Moreover, flammable hydrogen is released during the reduction of sodium borohydride to prepare nZVI. Therefore, in recent years, researchers have tried to synthesize nZVI by green methods, as shown in Figure 6i ~ K[87]. "Green" is reflected in the fact that the reducing agent is extracted from natural plants with high antioxidant capacity, such as green tea[88]. Polyphenols in leaves have strong antioxidant capacity, are non-toxic, biodegradable, and soluble in water at room temperature, and are suitable for reducing nZVI[87].
The plant extract covers the surface of the prepared nano-iron particles, on the one hand, the plant extract is used as a stabilizer to inhibit agglomeration and increase the specific surface area and adsorption sites; On the other hand, it can increase the surface functional groups and improve the adsorption performance of heavy metals[89].
The green synthesized nZVI was characterized by TEM, and the agglomeration phenomenon was alleviated, and the particle size was 10. 0 ~ 50.0 nm, which was smaller than that of the nZVI synthesized by the traditional method. The removal process of As by green synthesized nZVI followed the Freundlich isotherm adsorption model, and the adsorption capacity of ML-nZVI (synthesized by mulberry leaves) for As (Ⅴ) was 1329. 0 mg/G, which was higher than that of nZVI synthesized by sodium borohydride reduction method[90].

4 Summary and Prospect

At present, a large number of studies have been carried out on the removal of As (Ⅲ) and As (Ⅴ) from water by nZVI and its modified materials, which have been characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and other means.As well as thermodynamic and kinetic analysis, to understand the morphology, chemical composition and other information of nZVI and its modified materials, to clarify the removal behavior of arsenic by nZVI and its modified materials under different conditions, and to explore the removal mechanism.
The removal of As (Ⅲ) and As (Ⅴ) by nZVI under aerobic conditions is mainly based on adsorption and coprecipitation in the initial stage (< 1 H), and the iron oxides/hydroxides on the surface of nZVI play an important role in this process, which quickly adsorb As in the solution to the surface of nZVI and form arsenic-iron coprecipitation. The active oxides produced by Fe (0) corrosion oxidize As (Ⅲ) to less toxic As (Ⅴ). In particular, in the absence of oxygen, after a long reaction (> 24 H), As (Ⅲ) and As (Ⅴ) are gradually reduced to As (Ⅲ) and As (0) by Fe (0) and H2, and Fe (0) releases electrons outward through the defects of the oxidation shell, which reduces As (Ⅲ,Ⅴ) to As0 and encapsulates them in the oxidation shell.
The modified material of nZVI can show better removal performance, which is beneficial to the removal of arsenic. The modification method comprises the following steps of: (1) loading nZVI on a porous material, wherein the specific surface area of the porous material is obviously larger than that of the nZVI, and the nZVI can be fixed to reduce the loss of iron; (2) The agglomeration of nZVI is alleviated and the stability is improved by adding surface stabilizer; (3) doping noble metal to accelerate the formation of iron oxide/hydroxide and promote the adsorption and coprecipitation of arsenic by the material; And (4) green synthesis of nZVI, wherein the synthesis process is green and environment-friendly, and the price is low.
To sum up, nZVI and its modified materials have good removal effect on arsenic, but their promotion in practical application is still challenging: (1) The synthesis method is costly and complex, and it is difficult to form large-scale synthesis, so it is necessary to seek a synthesis method with lower price, simple operation and green environmental protection, and it should mainly focus on the exploration of new green reducing agents. (2) The removal efficiency of arsenic by nZVI and its modified materials is easily affected by coexisting ions and organic matter, while the actual water body has high ionic strength and contains a variety of natural organic matter, so it is necessary to develop a nZVI modification method with higher stability and anti-interference to ensure that it still has a high removal efficiency in the actual water body. (3) It is necessary to carry out the feasibility study of the actual arsenic-containing water body and the construction of supporting equipment. In situ groundwater remediation, the migration of focused materials and the stability of arsenic-containing products were studied to explore whether nZVI and its modified materials have the ability to treat a wide range of groundwater, as well as the safety of arsenic-containing products in groundwater for a long time. In the treatment of ex-situ arsenic-containing wastewater, we should focus on the construction of supporting equipment, how to regulate the relevant conditions and parameters in the actual operation process, and how to reduce the difficulty and cost of operation. (4) The safe disposal of solid waste after the treatment of arsenic-containing wastewater and whether it can be used as a resource need to be studied in depth. There is a lack of research on the toxicity of treated water, which needs further exploration.

References

Publishing order | Descend order by publishing year | Descend order by cited within
[1]

Guo G L, Zhou Q X, Ma L Q. Environ. Monit. Assess., 2006, 116(1/3): 513.
[2]

Rodríguez-Lado L, Sun G F, Berg M, Zhang Q, Xue H B, Zheng Q M, Johnson C A. Science, 2013, 341(6148): 866.
[3]

Smedley P L, Kinniburgh D G. Appl. Geochem., 2002, 17(5): 517.
[4]

Vahidnia A, van der Voet G B, de Wolff F A. Hum. Exp. Toxicol., 2007, 26(10): 823.
[5]

Han C Y, Li H Y, Pu H P, Yu H L, Deng L, Huang S, Luo Y M. Chem. Eng. J., 2013, 217: 1.
[6]

Andrianisa H A, Ito A, Sasaki A, Aizawa J, Umita T. Water Res., 2008, 42(19): 4809.
[7]

Donia A M, Atia A A, Mabrouk D H. J. Hazard. Mater., 2011, 191(1/3): 1.
[8]

Figoli A, Cassano A, Criscuoli A, Mozumder M S I, Uddin M T, Islam M A, Drioli E. Water Res., 2010, 44(1): 97.
[9]

Singh R, Singh S, Parihar P, Singh V P, Prasad S M. Ecotoxicol. Environ. Saf., 2015, 112: 247.
[10]

Yamani J S, Lounsbury A W, Zimmerman J B. Water Res., 2016, 88: 889.
[11]

Kang M, Kawasaki M, Tamada S, Kamei T, Magara Y. Desalination, 2000, 131(1/3): 293.
[12]

Zou Y D, Wang X X, Khan A, Wang P Y, Liu Y H, Alsaedi A, Hayat T, Wang X K. Environ. Sci. Technol., 2016, 50(14): 7290.
[13]

Wang Y L, Lin D H. Progress in Chemistry, 2017, 29(9): 1072.
[14]

(王艳龙, 林道辉. 化学进展, 2017, 29(9): 1072.).
[15]

Wang W. Doctor Dissertation of Tongji University, 2016.
[16]

(王伟. 同济大学博士论文, 2016.).
[17]

Karn B, Kuiken T, Otto M. Environ. Heal. Perspect., 2009, 117(12): 1813.
[18]

Yan W L, Lien H L, Koel B E, Zhang W X. Environ. Sci.: Processes Impacts, 2013, 15(1): 63.
[19]

Fan J, Guo Y H, Wang J J, Fan M H. J. Hazard. Mater., 2009, 166(2/3): 904.
[20]

Li X Q, Zhang W X. Langmuir, 2006, 22(10): 4638.
[21]

Keenan C R, Sedlak D L. Environ. Sci. Technol., 2008, 42(4): 1262.
[22]

Lee H, Lee H J, Kim H E, Kweon J, Lee B D, Lee C H. J. Hazard. Mater., 2014, 265: 201.
[23]

Li S L, Yan W L, Zhang W X. Green Chem., 2009, 11(10): 1618.
[24]

Crane R A, Dickinson M, Popescu I C, Scott T B. Water Res., 2011, 45(9): 2931.
[25]

Karlsson M N A, Deppert K, Wacaser B A, Karlsson L S, Malm J O. Appl. Phys. A, 2005, 80(7): 1579.
[26]

Yoo B Y, Hernandez S C, Koo B, Rheem Y, Myung N V. Water Sci. Technol., 2007, 55(1/2): 149.
[27]

Lawrinenko M, Wang Z J, Horton R, Mendivelso-Perez D, Smith E A, Webster T E, Laird D A, van Leeuwen J H. ACS Sustainable Chem. Eng., 2017, 5(2): 1586.
[28]

Wang C B, Zhang W X. Environ. Sci. Technol., 1997, 31(7): 2154.
[29]

Huang X Y, Wang W, Ling L, Zhang W X. Acta Chim. Sinica, 2017, 75(6): 529.
[30]

(黄潇月, 王伟, 凌岚, 张伟贤. 化学学报, 2017, 75(6): 529.).
[31]

Ling L, Zhang W X. Environ. Sci. Technol., 2017, 51(4): 2288.
[32]

Liu A R, Zhang W X. Anal., 2014, 139(18): 4512.
[33]

Wang C M, Baer D R, Amonette J E, Engelhard M H, Antony J, Qiang Y. J. Am. Chem. Soc., 2009, 131(25): 8824.
[34]

Ling L, Zhang W X. Environ. Sci. Technol. Lett., 2014, 1(7): 305.
[35]

Mondal K, Jegadeesan G, Lalvani S B. Ind. Eng. Chem. Res., 2004, 43(16): 4922.
[36]

Yong X J, Guan C, Zhang H, Jin Z W, Yao M. Environ. Eng., 2020, 38: 14.
[37]

(雍晓静, 关翀, 张昊, 金政伟, 姚敏. 环境工程, 2020, 38: 14.).
[38]

Zhang X X, Xia X F, Zhou W, Liu A R. Environmental Science and Technology, 2016, 39: 60.
[39]

( 张茜茜, 夏雪芬, 周文, 刘爱荣. 环境科学与技术, 2016, 39: 60.).
[40]

Kanel S R, Manning B, Charlet L, Choi H. Environ. Sci. Technol., 2005, 39(5): 1291.
[41]

Kanel S R, Grenèche J M, Choi H. Environ. Sci. Technol., 2006, 40(6): 2045.
[42]

Jegadeesan G, Mondal K, Lalvani S B. Environ. Prog., 2005, 24(3): 289.
[43]

Fendorf S, Eick M J, Grossl P, Sparks D L. Environ. Sci. Technol., 1997, 31(2): 315.
[44]

Xia X F, Hua Y L, Huang X Y, Ling L, Zhang W X. Acta Chim. Sinica, 2017, 75(6): 594.
[45]

(夏雪芬, 滑熠龙, 黄潇月, 凌岚, 张伟贤. 化学学报, 2017, 75(6): 594.).
[46]

Grossl P R, Eick M, Sparks D L, Goldberg S, Ainsworth C C. Environ. Sci. Technol., 1997, 31(2): 321.
[47]

Xia X F, Ling L, Zhang W X. Chemosphere, 2017, 168: 1597.
[48]

Manning B A, Hunt M L, Amrhein C, Yarmoff J A. Environ. Sci. Technol., 2002, 36(24): 5455.
[49]

Su C M, Puls R W. Environ. Sci. Technol., 2001, 35(7): 1487.
[50]

Yan W L, Ramos M A V, Koel B E, Zhang W X. J. Phys. Chem. C, 2012, 116(9): 5303.
[51]

Ramos M A V, Yan W L, Li X Q, Koel B E, Zhang W X. J. Phys. Chem. C, 2009, 113(33): 14591.
[52]

Ona-Nguema G, Morin G, Wang Y H, Foster A L, Juillot F, Calas G, Brown G E Jr. Environ. Sci. Technol., 2010, 44(14): 5416.
[53]

Tu ček J, Prucek R, Kolařík J, Zoppellaro G, Petr M, Filip J, Sharma V K, Zbořil R. ACS Sustainable Chem. Eng., 2017, 5(4): 3027.
[54]

Nurmi J T, Tratnyek P G, Sarathy V, Baer D R, Amonette J E, Pecher K, Wang C M, Linehan J C, Matson D W, Penn R L, Driessen M D. Environ. Sci. Technol., 2005, 39(5): 1221.
[55]

Yan W L, Vasic R, Frenkel A I, Koel B E. Environ. Sci. Technol., 2012, 46(13): 7018.
[56]

Yan W L, Ramos M A V, Koel B E, Zhang W X. Chem. Commun., 2010, 46(37): 6995.
[57]

Ling L, Huang X Y, Li M R, Zhang W X. Environ. Sci. Technol., 2017, 51(24): 14293.
[58]

Lu P, Zhu C. Environ. Earth Sci., 2011, 62: 1673.
[59]

Kartinen E O Jr, Martin C J. Desalination, 1995, 103(1/2): 79.
[60]

Wu C, Tu J W, Liu W Z, Zhang J, Chu S Q, Lu G N, Lin Z, Dang Z. Environ. Sci.: Nano, 2017, 4(7): 1544.
[61]

Wang Y, Sun L, Han T, Si Y B, Wang R F. J. Soils Sediments, 2016, 16(2): 486.
[62]

Su C M, Puls R W. Environ. Sci. Technol., 2001, 35(22): 4562.
[63]

Radu T, Subacz J L, Phillippi J M, Barnett M O. Environ. Sci. Technol., 2005, 39(20): 7875.
[64]

Cheng Z Q, van Geen A, Louis R, Nikolaidis N, Bailey R. Environ. Sci. Technol., 2005, 39(19): 7662.
[65]

Morgada M E, Levy I K, Salomone V, Farías S S, LÓpez G, Litter M I. Catal. Today, 2009, 143(3/4): 261.
[66]

Giasuddin A B M, Kanel S R, Choi H. Environ. Sci. Technol., 2007, 41(6): 2022.
[67]

Jiemvarangkul P, Zhang W X, Lien H L. Chem. Eng. J., 2011, 170(2/3): 482.
[68]

Phenrat T, Saleh N, Sirk K, Tilton R D, Lowry G V. Environ. Sci. Technol., 2007, 41(1): 284.
[69]

Greenlee L F, Torrey J D, Amaro R L, Shaw J M. Environ. Sci. Technol., 2012, 46(23): 12913.
[70]

Sikder M T, Kubota R, Akter M, Rahman M M, Hossain K F B, Rahaman M S, Banik S, Hosokawa T, Saito T, Kurasaki M. Desalination Water Treatment, 2019, 145: 202.
[71]

Bhowmick S, Chakraborty S, Mondal P, van Renterghem W, van den Berghe S, Roman-Ross G, Chatterjee D, Iglesias M. Chem. Eng. J., 2014, 243: 14.
[72]

Sun Y B, Ding C C, Cheng W C, Wang X K. J. Hazard. Mater., 2014, 280: 399.
[73]

Wang S C, Song Y D, Sun Y K. Progress in Chemistry, 2019, 31(2/3): 422.
[74]

(王舒畅, 宋亚丹, 孙远奎. 化学进展, 2019, 31(2/3): 422.).
[75]

Liu X, Lai D, Wang Y. J. Hazard. Mater., 2019, 361: 37.
[76]

Zhu H J, Jia Y F, Wu X, Wang H. J. Hazard. Mater., 2009, 172(2/3): 1591.
[77]

Liu M H, Wang Y H, Chen L T, Zhang Y, Lin Z. ACS Appl. Mater. Interfaces, 2015, 7(15): 7961.
[78]

Xiao J N, Gao B Y, Yue Q Y, Gao Y, Li Q. Chem. Eng. J., 2015, 262: 1226.
[79]

Sheng J, Fu H Y, Wang W, Zhang W X, Ling L. Environmental Chemistry, 2020, 39: 2959.
[80]

(盛杰, 傅浩洋, 王伟, 张伟贤, 凌岚. 环境化学, 2020, 39: 2959.).
[81]

Wang C, Luo H J, Zhang Z L, Wu Y, Zhang J, Chen S W. J. Hazard. Mater., 2014, 268: 124.
[82]

Chen C H, Xu J, Yang Z H, Zhang L, Cao C H, Xu Z H, Liu J Y. Appl. Surf. Sci., 2017, 425: 423.
[83]

Ling L, Zhang W X. RSC Adv., 2014, 4(64): 33861.
[84]

Alonso F, Beletskaya I P, Yus M. Chem. Rev., 2002, 102(11): 4009.
[85]

Chun C L, Baer D R, Matson D W, Amonette J E, Penn R L. Environ. Sci. Technol., 2010, 44(13): 5079.
[86]

Zhang W X, Wang C B, Lien H L. Catal. Today, 1998, 40(4): 387.
[87]

Babaee Y, Mulligan C N, Rahaman M S. J. Chem. Technol. Biotechnol., 2018, 93(1): 63.
[88]

Sepúlveda P, Rubio M A, Baltazar S E, Rojas-Nunez J, Sánchez Llamazares J L, Garcia A G, Arancibia-Miranda N. J. Colloid Interface Sci., 2018, 524: 177.
[89]

Zhao X Q, Dou X M, Mohan D, Pittman C U Jr, Ok Y S, Jin X. Chem. Eng. J., 2014, 247: 250.
[90]

Kanel S R, Goswami R R, Clement T P, Barnett M O, Zhao D. Environ. Sci. Technol., 2008, 42(3): 896.
[91]

Suguna M, Kumar N S, Sreenivasulu V, Krishnaiah A. Sep. Sci. Technol., 2014, 49(10): 1613.
[92]

Zou Y D, Wang X X, Khan A, Wang P Y, Liu Y H, Alsaedi A, Hayat T, Wang X K. Environ. Sci. Technol., 2016, 50(14): 7290.
[93]

Azzam A M, Shenashen M A, Selim M M, Yamaguchi H, El-Sewify I M, Kawada S, Alhamid A A, El-Safty S A. J. Phys. Chem. Solids, 2017, 109: 78.
[94]

Kim K R, Lee B T, Kim K W. J. Geochem. Explor., 2012, 113: 124.
[95]

Shahwan T, Sirriah S A, Nairat M, Boyacı E, Eroğlu A E, Scott T B, Hallam K R. Chem. Eng. J., 2011, 172(1): 258.
[96]

Chrysochoou M, Johnston C P, Dahal G. J. Hazard. Mater., 2012, 201/202: 33.
[97]

Nadagouda M N, Castle A B, Murdock R C, Hussain S M, Varma R S. Green Chem., 2010, 12(1): 114.
[98]

Poguberović S S, Krčmar D M, Maletić S P, Kónya Z, Pilipović D D T, Kerkez D V, Rončević S D. Ecol. Eng., 2016, 90: 42.

Funding

National Science Fund for Excellent Young Scholars(21822607)

National Natural Science Foundation of China(22176147)

100 Talents Program of Tongji University(22120200178)

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