Abstract

The removal of Cr(VI) from wastewater by adsorption from agro-industrial residues remain an attractive option since combines reasonable cost with the quality of effluents treated. This paper employs of parboiled-rice husk ash (RHA) and parboiled-rice husk ash chemically treated (RHAH⁺) as adsorbents for Cr(VI). The RHA and RHAH⁺ were characterized. It was studied the adsorption efficiency on adsorbent dosage, pH, chromium concentration, and interaction time. RHAH⁺ presented superior Cr(VI) removal, although both adsorbents have shown satisfactory results. The best results are obtained at pH 1.0, presenting 90.9% and 97.7% of Cr(VI) removal for RHA and RHAH⁺, respectively, in 5 mg L⁻¹ of Cr(VI) concentration at about 30 minutes. The adsorption of RHAH⁺ is governed by the Freundlich isotherm (R²_adj = 0.989) and kinetically by the pseudo-second order model (R²_adj = 0.991). The rice rusk ash represents an alternative low-cost and environment-friendly material that efficiently removes Cr(VI) from dilute aqueous solutions.

摘要

通过从农工业残留物中吸附去除废水中的 Cr(VI) 仍然是一个有吸引力的选择，因为它结合了合理的成本和所处理的废水的质量。本文采用稻壳灰（RHA）和经过化学处理的稻壳灰（RHAH ⁺）作为Cr(VI)的吸附剂。对 RHA 和 RHAH ⁺进行了表征。研究了吸附剂用量、pH、铬浓度和相互作用时间对吸附效率的影响。尽管两种吸附剂都显示出令人满意的结果，但RHAH ⁺表现出优异的 Cr(VI) 去除率。最好的结果是在 pH 1.0 时获得的，在 5 mg L ^-1中，RHA 和 RHAH ^{+的 Cr(VI) 去除率分别为 90.9% 和 97.7%}约 30 分钟时 Cr(VI) 浓度。RHAH ⁺的吸附受 Freundlich 等温线 (R ² _adj = 0.989) 和动力学上的准二级模型 (R ² _adj = 0.991) 控制。稻谷灰是一种替代的低成本和环保材料，可有效去除稀水溶液中的 Cr(VI)。