ABSTRACT

Presence of arsenic in groundwater, eventually in drinking water, has been recognised as a serious community health problem, due to its high toxic nature. Therefore, its removal is highly essential. Chitosan-based adsorbents have been widely used in water treatment in the present scenario due to their abundance and cost-effectiveness. However, there are some problems hindering its practical use, such as low tensile strength and low solubility in acidic mediums. Thus, in this work, to enhance the adsorption capacity of chitosan for the removal of As (V), it has been modified by grafting with monomer HEMA and SSS using gamma radiation. Modified chitosan was characterised by SEM and FTIR spectroscopy. In grafted and ungrafted chitosan, maximum adsorption capacity was found to be (16.8) mg/g and 1.78 (mg/g) using the 0.1 g of adsorbent dose at pH 3–4 in 35 min, and initial As (V) concentration of 60 mg/L. Isotherm study reveals the adsorption process followed by Langmuir isotherm model for both grafted and ungrafted chitosan. Kinetic study suggested that grafted chitosan followed pseudo second order whereas chitosan followed first order kinetics. The thermodynamics indicated that the adsorption process of modified chitosan for As (V) was endothermic and spontaneous in nature.

摘要

地下水中的砷，最终是饮用水中的砷，由于其剧毒性质而被认为是严重的社区健康问题。因此，将其去除是非常重要的。基于壳聚糖的吸附剂由于其丰度和成本效益而在本方案中已广泛用于水处理中。但是，存在一些阻碍其实际使用的问题，例如低拉伸强度和在酸性介质中的低溶解度。因此，在这项工作中，为了增强脱乙酰壳多糖的吸附能力，已通过使用γ射线接枝单体HEMA和SSS对其进行了改性。改性壳聚糖通过SEM和FTIR光谱表征。在接枝和未接枝的壳聚糖中，最大吸附量分别为（16.8）mg / g和1.78（mg / g）（使用0）。在35分钟内在pH 3-4下1 g吸附剂剂量，初始As（V）浓度为60 mg / L。等温线研究揭示了接枝的和未接枝的壳聚糖均遵循Langmuir等温线模型的吸附过程。动力学研究表明，接枝的壳聚糖遵循伪二级动力学，而壳聚糖遵循一级动力学。热力学表明，改性壳聚糖对As（V）的吸附过程是吸热的，自然而然的。