Abstract

Ammonia pollution of natural water can promote adverse undesirable environmental impacts on aquatic fauna, human and environment. Different techniques were elaborated for treatment of this pollution. Recently, polymer hydrogels have been successfully used as adsorbents of ammonium ions. Among the polysaccharides that can be used in the wastewater treatment, the alginates have the ability to adsorb various pollutants in the flexible channels by electrostatic interaction between the \({\text{NH}}_{4}^{ + }\) ions in aqueous solution and the –COO^– groups of the polymeric network. Alginates are natural biopolymers; they could be obtained from the brown seaweeds, extraction of alginates is often effectuated in a sodium form related to their fast solubility in cold water. In this work, sodium alginate solution was crosslinked by calcium divalent cations in the beads forms. The resulting beads are roughly spherical, when they are swollen; they become bigger in size, they were characterized by several techniques, which revealed that the sample contains different mineral and organic functional groups. Indeed, optimization of the contact time, temperature, pH, initial adsorbate concentration and initial adsorbent concentration has been studied. So, the maximal removal efficiency was 47.72% after 60 min, the favorable temperature of adsorption was 30°C where the maximal removal efficiency was 69.54%, the optimal pH is 7 with a maximum removal efficiency of 69.54%. Moreover, the removal efficiency decreased considerably from 69.54 to 34.26% at initial EAC varied from 10 mg-\({\text{NH}}_{4}^{ + }\)/L to 1000 mg-\({\text{NH}}_{4}^{ + }\)/L and an optimal initial adsorbent amount of 0.1 g where the removal efficiency was 69.54% and the equivalence EAC was 30.46 mg-\({\text{NH}}_{4}^{ + }\)/L. Furthermore, study of adsorption isotherms indicated that the process was obeyed to both models of Langmuir and Freundlich with R² values of 0.994 and 0.98 respectively, with a maximal adsorption capacity of 58.82 mg/g that calculated from Langmuir model. Finally, the spectral and the structural analyses after the adsorption process proved this phenomenon and allowed to apply these crosslinked beads-A in the treatment of waters charged with ammonium ions.

中文翻译：

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用于吸附去除铵离子的交联海藻酸钙多孔珠

摘要

天然水的氨污染会促进对水生动物、人类和环境的不利环境影响。为处理这种污染制定了不同的技术。最近，聚合物水凝胶已成功用作铵离子的吸附剂。在可用于废水处理的多糖中，藻酸盐具有通过\({\text{NH}}_{4}^{ + }\)离子之间的静电相互作用吸附柔性通道中的各种污染物的能力在水溶液和 –COO ^–聚合物网络的基团。海藻酸盐是天然生物聚合物；它们可以从棕色海藻中获得，藻酸盐的提取通常以钠形式进行，这与它们在冷水中的快速溶解性有关。在这项工作中，海藻酸钠溶液通过珠子形式的二价钙阳离子交联。得到的珠子在膨胀时大致呈球形；它们的尺寸变得更大，它们通过多种技术进行表征，这表明样品含有不同的矿物和有机官能团。实际上，已经研究了接触时间、温度、pH、初始吸附物浓度和初始吸附剂浓度的优化。因此，60 min 后的最大去除率为 47.72%，最佳吸附温度为 30°C，最大去除效率为 69。54%，最适pH为7，最大去除效率为69.54%。此外，在初始 EAC 从 10 mg-\({\text{NH}}_{4}^{ + }\) /L 至 1000 mg- \({\text{NH}}_{4}^{ + }\) /L 和最佳初始值吸附量为 0.1 g，其中去除效率为 69.54%，当量 EAC 为 30.46 mg- \({\text{NH}}_{4}^{ + }\) /L。此外，吸附等温线的研究表明，该过程符合Langmuir 和Freundlich 模型，R ²值分别为0.994 和0.98，根据Langmuir 模型计算的最大吸附量为58.82 mg/g。最后，吸附过程后的光谱和结构分析证明了这一现象，并允许将这些交联珠-A 用于处理带有铵离子的水。