School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang, 330013, Jiangxi, China.
Environ Sci Pollut Res Int. 2019 May;26(13):12776-12787. doi: 10.1007/s11356-019-04753-7. Epub 2019 Mar 16.
Heavy metal lead poses a great threat to organisms and the environment; the removal of lead has drawn more and more attention in recent years. In this paper, the sulfur-containing functional group was grafted onto the walnut shell with xanthate to synthesize a low-cost biosorbent (SWM) for the removal of lead in water. The synthesized adsorbent was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Brunner-Emmet-Teller (BET). The effects of pH, adsorbent dosage, contact time, initial Pb (II) concentration, and temperature on adsorption were investigated, and the adsorption properties of walnut shells before and after modification were compared. Moreover, adsorption kinetics, adsorption isotherms, and adsorption thermodynamics were studied. The sulfur-containing functional group was confirmed to be successfully grafted onto the walnut shell. The results showed that the adsorption performance of SWM was much better than the unmodified walnut shell due to complexation by sulfur-containing functional group and ion exchange. The Pb (II) adsorption onto SWM was found to follow Temkin isotherm model and has a good correlation with the pseudo-second-order kinetic model. In addition, the adsorption process was spontaneous and exothermic. All the results showed that the high adsorption performance and low cost of SWM make it a potential biosorbent in the treatment of lead-contaminated water.
重金属铅对生物和环境构成了巨大威胁；近年来，去除铅的研究越来越受到关注。本文通过黄原酸化法将含硫官能团接枝到核桃壳上，合成了一种用于去除水中铅的低成本生物吸附剂（SWM）。采用傅里叶变换红外光谱（FT-IR）、X 射线光电子能谱（XPS）、扫描电子显微镜（SEM）和 Brunner-Emmet-Teller（BET）对合成的吸附剂进行了表征。考察了 pH 值、吸附剂用量、接触时间、初始 Pb（II）浓度和温度对吸附的影响，并比较了修饰前后核桃壳的吸附性能。此外，还研究了吸附动力学、吸附等温线和吸附热力学。证实了含硫官能团已成功接枝到核桃壳上。结果表明，由于含硫官能团的络合作用和离子交换作用，SWM 的吸附性能比未改性的核桃壳要好得多。SWM 对 Pb（II）的吸附符合 Temkin 等温模型，与拟二级动力学模型具有良好的相关性。此外，吸附过程是自发的和放热的。所有结果表明，SWM 具有较高的吸附性能和较低的成本，使其成为处理含铅废水的潜在生物吸附剂。
