The present work reports a sustainable adsorption–reduction strategy for disposal of Cr(VI)-bearing wastes. By cross-linking between boehmite and chitosan to prepare amino-functionalized boehmite adsorbents, Cr(VI) could be adsorbed from the Cr(VI)-containing solutions by the adsorbents with the maximum adsorption capacity of 120.2 mg/g, which was improved about 3 times compared to that of boehmite. Adsorption mechanism showed that the Cr(VI) was adsorbed by complexing with −NH₂ bonds and exchanging with −OH groups of adsorbents. About 31% Cr(VI) was simultaneously reduced to Cr(III) by the reactive −OH and −NH₂ electron acceptor of adsorbents. After adsorption, the Cr(VI/III) and boehmite of adsorbents were dissolved in 25% H₂SO₄ solution, the remaining Cr(VI) was reduced to Cr(III) with 100% reduction yield, and the Cr_xAl_2–x(OH)_2y(SO₄)_8–y·nH₂O was prepared as product, while the insoluble chitosan was recycled in a closed loop. In application, column experiments results showed that the γ-AlOOH hazardous wastes could effectively dispose the Cr(VI)-containing textile wastewaters, and aluminum and chromium in the wastes could be comprehensively used to prepare chromium–aluminum tanning agent. The developed “waste-treating-waste” method leads to minimum pollutant emission and avoids the complex post-treatment problems.

中文翻译：

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Cr（VI）的可持续处置：吸附-还原策略，用于氨基官能化勃姆石危险固体废物处理纺织品废水

本工作报告了一种可持续的吸附减少战略，用于处理含Cr（VI）的废物。通过勃姆石和壳聚糖之间的交联制备氨基官能化勃姆石吸附剂，Cr（VI）可以从含Cr（VI）的溶液中被吸附剂吸附，最大吸附容量为120.2 mg / g。是勃姆石的3倍。吸附机理表明Cr（VI）通过与-NH ₂键络合并与-OH基团交换而被吸附。通过吸附剂的反应性-OH和-NH ₂电子受体，同时将约31％的Cr（VI）还原为Cr（III）。吸附后，将吸附剂的Cr（VI / III）和勃姆石溶解在25％H ₂ SO _4中溶液中，剩余的Cr（VI）以100％的还原率还原为Cr（III），并制备了Cr _x Al _{2– x}（OH）_{2 y}（SO ₄）_{8– y} · n H ₂ O ，而不溶性壳聚糖则在闭环中循环使用。在应用中，柱实验结果表明，γ-AlOOH危险废物可以有效地处理含Cr（VI）的纺织废水，并且废物中的铝和铬可以综合用于制备铬铝制革剂。先进的“废物处理-废物”方法可将污染物排放降至最低，并避免了复杂的后处理问题。