Department of Environmental Engineering, Akdeniz University, 07058 Antalya, Turkey E-mail:
Water Sci Technol. 2021 Mar;83(5):1152-1166. doi: 10.2166/wst.2021.057.
Heavy metals become inevitable pollutants that are toxic to life. Lots of treatment methods are available; adsorption is a cheap option. Metals are mostly found as mixtures in wastewaters. Taking this into account, a natural composite adsorbent aims to remove multiple heavy metals (Pb, Cu, Cd). Alginate was combined with clinoptilolite to form alginate - clinoptilolite (A-C) beads. First, factors influencing the removal efficiency of metals were investigated. Then, continuous column experiments were performed to evaluate the real application potential of the adsorbent. A-C beads preferably adsorbed Pb. Batch experiments showed metal uptake reached equilibrium after 24 hours and kinetics were compatible with the first-order. Also, pH values near neutral levels were observed to increase heavy metal removal. On the other hand, adsorption equilibrium was well described by the Langmuir model for Cu and Cd and by the Freundlich model for Pb. The highest heavy metal uptake was calculated as 2,145 mg /g A-C beads for Pb. Continuous column operations were suggested to apply low flow rates (<2 mL/min) and heavy metal concentration (<10 mg/L) for effectiveness. A-C beads can be a good candidate for mixed heavy metal removal composed of environmentally friendly and low-cost materials.
重金属成为对生命有毒的不可避免的污染物。有很多处理方法可用；吸附是一种廉价的选择。金属大多以混合物的形式存在于废水中。考虑到这一点，一种天然复合吸附剂旨在去除多种重金属（Pb、Cu、Cd）。海藻酸钠与斜发沸石结合形成海藻酸钠-斜发沸石（A-C）珠。首先，研究了影响金属去除效率的因素。然后，进行连续柱实验以评估吸附剂的实际应用潜力。A-C 珠更优先吸附 Pb。批实验表明，金属吸附在 24 小时后达到平衡，动力学与一级动力学相匹配。此外，观察到接近中性水平的 pH 值可提高重金属的去除率。另一方面，Cu 和 Cd 的吸附平衡很好地描述了 Langmuir 模型，Pb 的吸附平衡很好地描述了 Freundlich 模型。对于 Pb，A-C 珠的最大重金属吸附量计算为 2145mg/g。建议连续柱操作应用低流速（<2mL/min）和低重金属浓度（<10mg/L）以提高效率。A-C 珠可以成为由环保且低成本材料组成的混合重金属去除的良好候选物。
