Khamwichit Attaso, Dechapanya Wipawee, Dechapanya Wipada
School of Engineering and Technology, Walailak University, 222 Thaiburi, Thasala, Nakhon Si Thammarat, 80160, Thailand.
Excellent Research Center of Palm Oil and Biomass, Walailak University, 222 Thaiburi, Thasala, Nakhon Si Thammarat, 80160, Thailand.
Heliyon. 2022 Jun 2;8(6):e09610. doi: 10.1016/j.heliyon.2022.e09610. eCollection 2022 Jun.
Among available technologies to remove heavy metals from wastewater, biosorption has gained more attention due to its high removal efficiency, friendly operation, and inexpensive cost. Despite many studies on metal adsorption from single ion solutions, kinetics and isotherms of binary metal ions simultaneously adsorbed onto biosorbents have not been thoroughly investigated to provide insight on involving mechanisms. This study explored the adsorption potential of untreated venus shells (UVS) that can be utilized in economical and environmentally-friendly ways. In this work, UVS of different sizes were prepared without chemical treatment as a biosorbent. Characterization of UVS was accomplished using nitrogen adsorption isotherm, FTIR, and SEM-EDX. Batch adsorption was carried out to study the effect of initial metal ion concentration, adsorbent dosage, and size on removing Cu(II) and Zn(II) from a binary solution of both metal ions using UVS. The experimental values of maximum adsorption capacities of Cu(II) and Zn(II) were 0.446 and 0.465 mg/g, respectively. The adsorption data were analyzed using the pseudo-first order, pseudo-second order, Elovich, and intraparticle diffusion rate equations. The pseudo-second order and the intraparticle diffusion model yielded the best fit to the experimental data for Cu(II) and Zn(II) ions, respectively. The equilibrium isotherm was examined using the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich (D-R), and Elovich models. The Freundlich model best fits the Cu(II) and Zn(II) equilibrium adsorption data. The results indicated that the adsorption of Cu(II) and Zn(II) onto UVS-600 adsorbent could undergo a chemisorption mechanism. Both metal ions in an aqueous solution were competitively adsorbed onto the heterogeneous active sites available on the shell surfaces. Cu(II) and Zn(II) ions in the binary system could result in ionic interference between the adsorbed ions and the active sites.
在从废水中去除重金属的现有技术中，生物吸附因其高去除效率、操作友好且成本低廉而受到更多关注。尽管对单离子溶液中金属吸附的研究很多，但对于同时吸附在生物吸附剂上的二元金属离子的动力学和等温线尚未进行深入研究，以深入了解其中涉及的机制。本研究探索了未经处理的维纳斯贝壳（UVS）的吸附潜力，其可通过经济且环保的方式加以利用。在这项工作中，制备了不同尺寸的未经化学处理的UVS作为生物吸附剂。使用氮气吸附等温线、傅里叶变换红外光谱（FTIR）和扫描电子显微镜-能谱仪（SEM-EDX）对UVS进行了表征。进行了批量吸附实验，以研究初始金属离子浓度、吸附剂用量和尺寸对使用UVS从两种金属离子的二元溶液中去除Cu(II)和Zn(II)的影响。Cu(II)和Zn(II)的最大吸附容量实验值分别为0.446和0.465 mg/g。使用伪一级、伪二级、埃洛维奇和颗粒内扩散速率方程对吸附数据进行了分析。伪二级和颗粒内扩散模型分别对Cu(II)和Zn(II)离子的实验数据拟合效果最佳。使用朗缪尔、弗伦德利希、特姆金、杜比宁-拉杜舍维奇（D-R）和埃洛维奇模型对平衡等温线进行了研究。弗伦德利希模型最适合Cu(II)和Zn(II)的平衡吸附数据。结果表明，Cu(II)和Zn(II)在UVS-600吸附剂上的吸附可能经历化学吸附机制。水溶液中的两种金属离子竞争性地吸附在贝壳表面可用的异质活性位点上。二元体系中的Cu(II)和Zn(II)离子可能导致吸附离子与活性位点之间的离子干扰。
