Abstract：
Lead is used in many industries such as refining, mining, battery manufacturing, smelting. Releases of lead from these industries is one of the major public health concerns due to widespread persistence in the environment and its resulting poisoning character. In this work, the castor seed shell (CSS) waste was exploited for preparing a beneficial bio-adsorbent for removal of Pb(II) ions from water. The raw CSS was modified with H3PO4 at different acid concentrations, impregnation ratios, activation times, and temperatures. An optimum adsorption capacity was observed for CSS modified with 2 M acid, 5 mL g-1 solid to liquid ratio, treated at 95 °C for 160 min. Exploiting acid modification, the SEM, XRD, and FTIR analyses show some alterations in functional groups and the surface morphology of the biomass. The impacts of physiochemical variables (initial lead ions concentration, pH, adsorbent dose and adsorption time) on the lead removal percentage were investigated, using response surface methodology (RSM). Maximum removal of 72.26% for raw CSS and 97.62% for modified CSS were obtained at an initial lead concentration (50 mg L-1), pH (5.7), adsorption time (123 min) and adsorbent dosage (1.1 g/100 mL). Isothermal and kinetics models were fitted to adsorption equilibrium data and kinetics data for the modified CSS and the adsorption system was evaluated thermodynamically and from the energy point of view. Isothermal scrutinization indicated the mono-layer nature of adsorption, and the kinetics experimental outcomes best fitted with the pseudo-second-order, implying that the interaction of lead ions and hot acid-treated CSS was the rate-controlling phenomenon of process. Overall, results illustrated that the hot acid-treated biomass-based adsorbent can be considered as an alternative bio-adsorbent for removing lead from water media.
摘要：
铅用于许多行业，如炼油，采矿,电池制造,冶炼。由于环境中的广泛持久性及其导致的中毒特性，这些行业的铅释放是主要的公共卫生问题之一。在这项工作中,蓖麻种子壳（CSS）废物被用于制备有益的生物吸附剂，以从水中去除Pb（II）离子。用H3PO4在不同的酸浓度下修改原始CSS，浸渍比，激活时间,和温度。观察到用2M酸改性的CSS的最佳吸附能力，5mLg-1固液比，在95°C下处理160分钟。开发酸改性，SEM，XRD,和FTIR分析显示了生物质的官能团和表面形态的一些变化。物理化学变量的影响(初始铅离子浓度，pH值,吸附剂用量和吸附时间)对铅去除率进行了考察，使用响应面法(RSM)。在初始铅浓度（50mgL-1）下，原始CSS的最大去除率为72.26％，改良CSS的最大去除率为97.62％，pH（5.7），吸附时间(123min)和吸附剂用量(1.1g/100mL)。等温和动力学模型拟合了改性CSS的吸附平衡数据和动力学数据，并从热力学和能量角度评估了吸附系统。等温仔细检查表明吸附的单层性质，动力学实验结果最符合伪二阶，暗示铅离子与热酸处理CSS的相互作用是过程的速率控制现象。总的来说,结果表明，热酸处理的生物质基吸附剂可以作为一种替代的生物吸附剂去除水介质中的铅。
