基于建筑废弃物的轻石制备及其对重金属的吸附性能

利用废弃玻璃和水泥块制备一种新型轻石,研究了其对Cr3+、As3+、Pb2+、Cu2+、Zn2+的吸附效果及吸附竞争影响。采用吸附动力学模型、吸附等温模型和傅里叶红外光谱研究其吸附作用,并考察了轻石的循环使用性能。结果表明:轻石对Cr3+、As3+、Pb2+、Cu2+、Zn2+的吸附量分别为64,110,79,161,161 μg/mg;轻石吸附重金属主要与其表面的官能团和化学键有关,吸附过程更符合准二级动力学模型,吸附等温线均可由Langmuir和Freundlich模型较好模拟;当5种重金属共存时,吸附竞争性。5种重金属离子的去除率顺序为Cr3+＞Cu2+＞Zn2+＞As3+＞Pb2+;使用0.1 mol/L的HCl作为解吸剂,轻石经过6次循环使用后,5种重金属的去除率仍在50%以上,说明新型轻石具有良好的吸附性能和循环使用性能,所制备的新型轻石吸附剂符合当下"以废治废"的治理趋势,具有广阔的应用前景。

PREPARATION OF PUMICE BASED ON CONSTRUCTION WASTE AND ITS ADSORPTION PERFORMANCE ON HEAVY METALS

In this paper, new pumice was prepared with waste glass and cement blocks, and its adsorption effect and competition effect on Cr3+, As3+, Pb2+, Cu2+ and Zn2+ were studied. The adsorption kinetics model, adsorption isotherm model and Fourier infrared spectroscopy were used to study the removal of heavy metals, and the recycling performance of pumice was investigated. The results showed that the adsorption capacity of pumice for Cr3+, As3+, Pb2+, Cu2+ and Zn2+ were 64, 110, 79, 161, 161 μg/mg, respectively. The adsorption of heavy metals was mainly related to the functional groups and chemical bonds on the surface. The adsorption process fitted well with the quasi-second-order kinetic model, and the adsorption isotherms was well simulated by Langmuir model and Freundlich model. When the five heavy metals coexisted, the adsorption competition reflected the adsorption preference by pumice, and the removal rate of the heavy metal ions followed the order of Cr3+>Cu2+>Zn2+>As3+>Pb2+. After six cycles, the removal rate of five heavy metals was still above 50%, indicating that the new pumice had good adsorption and recycling performance. The pumice adsorbent prepared with construction waste conformed to the concept of Using Waste to Treat Waste and had broad application prospects.