A macroporous anion exchange resin containing high density of positively-charged quaternary ammonium functional groups and supporting binary Fe/Mn oxides nanoparticles (HA502P-Fe/Mn) was synthesized for simultaneous As(III)oxidation and As(V) adsorption within a single bead. Various preparation parameters were investigated and optimized to achieve the highest As(III) removal efficiency, including metal oxides type, supporting materials, preparation solvents, and number of loading cycles. The results from five imaging techniques (SEM-EDX, TEM, XRD, XANES, EXAFS) confirmed that amorphous ferric and manganese oxides nanoparticles were successfully dispersed throughout the matrix of the parent macroporous anion exchanger. The changes in oxidation state of the Mn oxides from +4 to +2 and + 2 to +4 were observed by XANES during As(III) removal and regeneration runs, respectively. The EXAFS was used to investigate the neighborhood atoms surrounding arsenic during As(III) removal by HA502P-Fe/Mn. The bond distance between AsFe and AsMn of HA502P-Fe/Mn are 3.35 and 2.94 Å, respectively, suggesting that As(III) was oxidized to As(V) and adsorbed on the surface of Fe(III) and Mn(IV) oxide nanoparticles by formation of inner-sphere complex. As(III) was oxidized by MnO₂ nanoparticles under the absence of oxygen environment and only As(V) was observed after adsorption. The equilibrium As(III) sorption isotherms, effect of pH, competing ions, and NOM were also evaluated. Fixed-bed column experiments using NSF challenge water standard 53 (300 μg As(III)/L, pH 6.5) were carried out and found that the material can remove As(III) equivalent to 4300 bed volumes (BVs) compared with 2000 BVs using commercial arsenic selective material (Layne-RT). The exhausted material can be regenerated using 10 BVs of regeneration solution and 98% of adsorbed arsenic can be recovered.

合成了具有高密度带正电的季铵官能团并负载二元Fe / Mn氧化物纳米粒子（HA502P-Fe / Mn）的大孔阴离子交换树脂，用于在单个微珠中同时进行As（III）氧化和As（V）吸附。对各种制备参数进行了研究和优化，以实现最高的As（III）去除效率，包括金属氧化物类型，载体材料，制备溶剂和加样循环次数。五种成像技术（SEM-EDX，TEM，XRD，XANES，EXAFS）的结果证实，无定形三氧化二铁和锰氧化物纳米颗粒已成功分散在母体大孔阴离子交换剂的整个基质中。XANES分别在去除As（III）和再生过程中观察到Mn氧化物的氧化态从+4变为+2，从+2变为+4。EXAFS用于研究通过HA502P-Fe / Mn去除As（III）时砷周围的邻近原子。As之间的键距HA502P-Fe / Mn的Fe和As Mn分别为3.35和2.94Å，表明As（III）被氧化为As（V）并通过形成而吸附在Fe（III）和Mn（IV）氧化物纳米颗粒的表面上内圈复合体。As（III）被MnO ₂氧化纳米颗粒在无氧环境下吸附后仅观察到As（V）。还评估了平衡的As（III）吸附等温线，pH，竞争离子和NOM的影响。进行了使用NSF挑战水标准品53（300μgAs（III）/ L，pH 6.5）的固定床实验，发现与2000 BV相比，该材料可以去除相当于4300床体积（BV）的As（III）。使用商业砷选择性材料（Layne-RT）。可以使用10 BV的再生溶液对废料进行再生，并且可以回收98％的吸附砷。