The structural effect of Fe-, Zr- and FeZr-modified clinoptilolite-, mordenite- and chabazite-rich tuffs was examined on the As(V) sorption from aqueous solutions. Batch experiments were conducted considering the sorbent mass, contact time and pH. The most probable sites where Fe and Zr species could be located in the zeolite frameworks after the modification were described: Na⁺ exchangeable sites in the 10-ring and 8-ring channels of clinoptilolite, and inside the 12-ring and 8-ring channels and 8-ring side pockets of mordenite; Na⁺, K⁺ and Ca²⁺ sites within the D6R cages and barrel-shape cavities of chabazite. As(V) sorption capacities of Zr-modified materials (0.062 ± 0.008 mg/g) were higher than the Fe-modified ones (0.031 ± 0.007 mg/g). Isotherm results were best adjusted to the Freundlich model; FeZr-modified materials presented the highest affinity for arsenic. Estimated free energy values from the Dubinin-Radushkevich isotherm model suggested an ion exchange process. Kinetic data were well described by the pseudo-second order and intraparticle diffusion models, thus the sorption rate could have been controlled by two steps, the transfer of arsenic through the channel systems and the chemical interactions. Based on data modeling for the pH effect, zeolitic materials showed an optimal sorption in the pH range from 2 to 6; the major arsenic species involved in the sorption process were H₂AsO₄⁻ and HAsO₄²⁻. The mechanism for As(V) removal by the FeZr-modified zeolites was through the formation of an inner sphere complex via ion exchange.

研究了Fe，Zr和FeZr改性的斜发沸石，丝光沸石和菱沸石的凝灰岩的结构效应对从水溶液中吸附As（V）的影响。考虑吸附剂质量，接触时间和pH进行批量实验。描述了改性后沸石骨架中最可能存在Fe和Zr物种的位点：斜发沸石的10环和8环通道以及12环和8环通道内的Na ⁺可交换位点。和8环的丝光侧袋；Na ⁺，K ⁺和Ca ²⁺D6R笼内的位置和菱沸石的桶形空腔。Zr改性材料的As（V）吸附容量（0.062±0.008 mg / g）高于Fe改性材料（0.031±0.007 mg / g）。等温线结果最好根据Freundlich模型进行调整；FeZr改性的材料对砷具有最高的亲和力。从Dubinin-Radushkevich等温线模型估计的自由能值表明了离子交换过程。动力学数据通过伪二级和颗粒内扩散模型得到了很好的描述，因此吸附速率可以通过两个步骤控制，砷通过通道系统的转移和化学相互作用。根据有关pH效应的数据模型，沸石材料在2至6的pH范围内表现出最佳的吸附性能。₂ ASO ₄ ^-和HAsO ₄ ^2-。FeZr改性沸石去除As（V）的机理是通过离子交换形成内球络合物。