Abstract：
The utilization of gypsum and biomass in environmental remediation has become a novel approach to promote waste recycling. Generally, raw waste materials exhibit limited adsorption capacity for heavy metal ions (HMIs) and often result in poor solid-liquid separation. In this study, through co-pyrolysis with corncob waste, titanium gypsum (TiG) was transformed into magnetic adsorbents (GCx, where x denotes the proportion of corncob in the gypsum-corncob mixture) for the removal of Cd(II) and Pb(II). GC10, the optimal adsorbent, which was composed primarily of anhydrite, calcium sulfide, and magnetic Fe3O4, exhibited significantly faster adsorption kinetics (rate constant k1 was 218 times and 9 times of raw TiG for Cd(II) and Pb(II)) and higher adsorption capacity (Qe exceeded 200 mg/g for Cd(II) and 400 mg/g for Pb(II)) than raw TiG and previous adsorbents. Cd(II) removal was more profoundly inhibited in a Cd(II) + Pb(II) binary system, suggesting that GC10 showed better selectivity for Pb(II). Moreover, GC10 could be easily separated from purified water for further recovery, due to its high saturation magnetization value (6.3 emu/g). The superior removal capabilities of GC10 were due to adsorption and surface precipitation of metal sulfides and metal sulfates on the adsorbent surface. Overall, these waste-derived magnetic adsorbents provide a novel and sustainable approach to waste recycling and the deep purification of multiple HMIs.
摘要：
石膏和生物质在环境修复中的利用已成为促进废物回收的新途径。一般来说,原始废料对重金属离子（HMIs）的吸附能力有限，通常会导致固液分离不良。在这项研究中,通过与玉米芯废料共热解，钛石膏(TiG)转化为磁性吸附剂(GCx，其中x表示石膏-玉米芯混合物中玉米芯的比例），用于去除Cd（II）和Pb（II）。GC10，最佳吸附剂，主要由硬石膏组成，硫化钙，和磁性Fe3O4，表现出明显更快的吸附动力学（速率常数k1是Cd（II）和Pb（II）的原TiG的218倍和9倍）和更高的吸附容量（Qe超过200mg/g的Cd（II）和400mg/g的Pb（II））。在Cd(II)+Pb(II)二元体系中Cd(II)的去除受到更深刻的抑制，表明GC10对Pb(II)表现出更好的选择性。此外，GC10可以很容易地从纯净水中分离以进一步回收，由于其高饱和磁化强度值（6.3emu/g）。GC10的优异去除能力是由于金属硫化物和金属硫酸盐在吸附剂表面的吸附和表面沉淀。总的来说,这些废物衍生的磁性吸附剂为废物回收和多种HMI的深度纯化提供了一种新颖且可持续的方法。
