During the tanning step, 30–40% of trivalent chromium remains in the solid and liquid wastes, generating highly polluted sewage. In this study, powdered marble was used as a low-cost adsorbent to remove trivalent chromium from a synthetic solution and a real tanning effluent. Batch adsorption experiments on powdered marble were performed. After incubation, samples were filtered and the uptake of chromium was determined. A 3-level Box-Behnken Design was used to study the combined effect of initial chromium concentration, pH values and adsorbent dose on the removal of trivalent chromium. The results showed that the maximum uptake (> 99%) was obtained at a chromium initial concentration of 0.758 g/L, pH = 5.0 and using 6% (w:v) of powdered marble. Adsorption isotherm was satisfactorily described by Langmuir model. The toxicity of the tanning effluent was examined before and after adsorption. Phytotoxicity (Lepidium sativum) assays revealed an improvement of the germination index rising from 0 to 35% before and after adsorption, respectively. Microtoxicity (Escherichia coli) assays showed a decrease in the growth inhibition percentage going from 100 to 31% following the adsorption experiment using raw tanning effluent. Desorption study indicated that nearly 45% of the adsorbed trivalent chromium was recovered using 4% (v:v) HCl. Overall, results showed that powdered marble is an effective and an economical alternative with great potential for trivalent chromium recovery.

在鞣制步骤中，30-40% 的三价铬残留在固体和液体废物中，产生高度污染的污水。在这项研究中，粉状大理石被用作一种低成本的吸附剂，以从合成溶液和真正的鞣制废水中去除三价铬。对粉状大理石进行了批量吸附实验。孵育后，过滤样品并测定铬的吸收量。3 级 Box-Behnken 设计用于研究初始铬浓度、pH 值和吸附剂剂量对三价铬去除的综合影响。结果表明，在铬初始浓度为 0.758 g/L、pH = 5.0 和使用 6% (w:v) 的粉状大理石时，获得最大吸收 (> 99%)。Langmuir 模型令人满意地描述了吸附等温线。在吸附之前和之后检查鞣制流出物的毒性。植物毒性（Lepidium sativum)测定显示，在吸附前后，发芽指数分别从 0% 提高到 35%。微毒性（大肠杆菌）试验表明，在使用生鞣废水进行吸附实验后，生长抑制百分比从 100% 下降到 31%。解吸研究表明，使用 4% (v:v) HCl 回收了近 45% 的吸附三价铬。总体而言，结果表明粉状大理石是一种有效且经济的替代品，具有巨大的三价铬回收潜力。