FeOOH and Mn₈O₁₀Cl₃ modified zeolites for As(V) removal in aqueous medium

Abstract

BACKGROUND Arsenic in drinking water poses serious potential health risks in more than 30 countries with total affected population of around 100 million people. The present study is devoted to the development of innovative sorbents based on zeolite materials for As(V) sorption by modifying raw materials with iron oxyhydroxide and manganese oxychloride. Natural clinoptilolite and synthetic zeolite A were modified in order to obtain improved sorption of As(V). Sorption properties of newly developed sorbents were studied. Zeolites containing natural clinoptilolite are chosen due to relatively low cost and their broad use in industrial production as well as characteristic large surface area. RESULTS Results obtained indicate that modification of zeolites with FeOOH and Mn8O10Cl3 significantly improves the As(V) sorption capacity of newly developed materials. As(V) sorption on FeOOH‐modified aluminosilicates follows the Langmuir model, while on unmodified aluminosilicates it is described by the Freundlich model. As(V) sorption kinetics on both modified and unmodified materials most precisely can be described by Lagergren's pseudo‐second‐order kinetic model. Elevated As(V) concentration on the surface of Mn8O10Cl3 crystals and amorphous FeOOH indicates these compounds as responsible for sorption increase. CONCLUSION Developed sorbents show improved performance in comparison with their unmodified counterparts, with a dramatic increase in As(V) sorption capacity up to 99.3 times in the case of FeOOH‐modified calcium zeolite A. These materials have great potential for As(V) removal in aqueous medium. © 2017 Society of Chemical Industry

Use of Synthetic and Natural Zeolites Tailored for As(V) Sorption

“…SEM micrographs (Figure 2) indicate that obtained materials FeMn-Slov, Fe-Khol and Fe-13X are modified with an amorphous compound, which is also further proved using EDX (for more details, also see source [17]). SEM micrographs (Figure 2) indicate that obtained materials Mn-4A, Mn-Slov(1), Mn-Slov(2), FeMn-Slov and CaMn-Slov are modified with manganese compounds.…”

“…Altogether, using these methods, 11 novel materials were synthesized and are described in this chapter. Additionally, FeOOH-modified zeolites A were obtained and described in the following source [17]. It should be also noted that another aluminosilicate, clay montmorillonite was modified using a similar approach and described in another work [39].…”

“…Third method is based on the first method, adapted to be applicable for efficient modification of powders (as in case of Fe-4A and Fe-5A described in another work [17]). The idea is to conduct a reaction in the wet FeOOH mass, simplifying and accelerating modification process.…”

“…SEM micrographs (Figure 2) indicate that obtained materials Mn-4A, Mn-Slov(1), Mn-Slov(2), FeMn-Slov and CaMn-Slov are modified with manganese compounds. In case of Mn-4A and Mn-Slov(2), manganese compound is amorphous, while for Mn-Slov(1), FeMn-Slov and CaMn-Slov a new crystalline phase (Mn 8 O 10 Cl 3 )i s obtained (more details can be found in source [17]). …”

“…Advantages of zeolitic sorbents are as follows: Generally, they are environmentally friendly, relatively cheap and can be treated for secondary use. Considering affinity of metalloids to interact with Fe and Mn-containing compounds [17], studies of As(V) sorption can be promoted in direction of using iron-and manganese-modified zeolites.…”