This present study depicts the successful employment of fixed-bed column for total chromium removal from tannery wastewater in dynamic mode using sodium alginate-powdered marble beads (SA–Marble) as adsorbent. The SA–Marble composite beads prepared were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and Brunauer, Emmett and Teller (BET) method. The adsorption process performance of this bio-sorbent was examined in batches and columns for real effluent (tannery wastewater). After 90 min, the total chromium removal efficiency could be kept above 90% in the batch experiment. The adsorption kinetics fit better with the pseudo-second-order model, indicating the chemisorption process and the adsorption capacity of about 67.74 mg g⁻¹ at 293 K (C0 = 7100 mg L⁻¹) was obtained. Additionally, dynamic experiments indicate that the total chromium removal efficiency could be maintained above 90% after 120 min at 293 K and 60 min at 318 and 333 K; it’s an endothermic but rapid process. The effects of two adsorption variables (Temperature and time) were investigated using central composite design (CCD), which is a subset of response surface methodology (total Cr, COD, sulfate, and total phosphorus percentage removal). This work paves a new avenue for synthesizing SA–Marble composite beads and provides an adsorption efficiency of total chromium removal from tannery wastewater.

Graphical abstract

中文翻译：

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使用新型多孔复合珠连续处理高浓度制革废水：中心复合材料设计优化研究

本研究描述了使用海藻酸钠粉大理石珠（SA-Marble）作为吸附剂，成功采用固定床柱以动态模式去除制革废水中的总铬。制备的 SA-大理石复合珠通过傅里叶变换红外光谱 (FTIR)、X 射线衍射 (XRD)、扫描电子显微镜 (SEM)、能量色散 X 射线光谱 (EDS) 以及 Brunauer、Emmett 和 Teller (Brunauer、Emmett 和 Teller) 进行了表征。 BET）方法。针对实际废水（制革废水），分批和分柱检查了这种生物吸附剂的吸附过程性能。90 min后，批量实验中总铬去除率可保持在90%以上。吸附动力学更符合准二阶模型，表明化学吸附过程，在293 K（C0 = 7100 mg L ^-1）时获得约67.74 mg g ^{-1的吸附容量。}另外，动态实验表明，293 K 120 min、318、333 K 60 min后总铬去除率仍能保持在90%以上；这是一个吸热但快速的过程。使用中心复合设计 (CCD) 研究了两个吸附变量（温度和时间）的影响，CCD 是响应面方法（总 Cr、COD、硫酸盐和总磷去除百分比）的子集。这项工作为合成SA-大理石复合珠开辟了一条新途径，并提供了从制革废水中去除总铬的吸附效率。

图形概要