Department of Chemistry, Karaj Branch, Islamic Azad University, Karaj, Iran.
Biobased Monomers and Polymers Division (BIOBASED Division), Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran.
Water Environ Res. 2020 Jun;92(6):934-947. doi: 10.1002/wer.1288. Epub 2020 Jan 6.
In the present study, we investigated the performance of hydrogel-rice husk biochar composites, as low-cost, alternative, and biocompatible adsorbents for separating nitrate ions from aqueous solutions. Hydrogel-biochar composite was synthesized at dosages of 2.5%, 3.6%, 4.8%, and 9.6% weight ratios of biochar. The composite was characterized by several common methods including FTIR, SEM, TEM, TGA, and DSC. In addition, the effect of contact time, initial concentration of nitrate ions, and solution pH were considered. The maximum removal of nitrate was about 34.3% at acidic pH (pH = 3) using 0.02 g of adsorbent in 25 ml of nitrate solution with the initial concentration (20 mg/L) and temperature of 25°C for 60 min. Based on the findings, 5% biochar in the composite was the optimal dosage. Adsorption kinetic study revealed that this process followed the first-order kinetic model. The experimental equilibrium adsorption data were tested by the Temkin isotherm model with R > 0.97. Based on the thermodynamic studies, the adsorption process was endothermic and spontaneous. Overall, the results suggested that the obtained composite can be specifically employed for removal of contaminations from aqueous solutions. PRACTITIONER POINTS: Hydrogel-biochar composite provides a biocompatible and cost-effective adsorbent. Hydrogel-biochar composite was applied to eliminate nitrate from aqueous solutions. Nitrate removal increased in the synthesized composite upon elevation of the weight ratio of biochar to 0.2 g.
在本研究中，我们研究了水凝胶-稻壳生物炭复合材料的性能，将其作为从水溶液中分离硝酸盐离子的低成本、替代和生物相容的吸附剂。水凝胶-生物炭复合材料以生物炭的 2.5%、3.6%、4.8%和 9.6%重量比合成。通过几种常见的方法对复合材料进行了表征，包括 FTIR、SEM、TEM、TGA 和 DSC。此外，还考虑了接触时间、硝酸盐初始浓度和溶液 pH 的影响。在 25°C 下，使用 0.02g 吸附剂在 25ml 硝酸盐溶液中，初始浓度（20mg/L）和接触时间为 60min 时，在酸性 pH（pH=3）下硝酸盐的最大去除率约为 34.3%。根据研究结果，复合材料中 5%的生物炭是最佳用量。吸附动力学研究表明，该过程遵循一级动力学模型。实验平衡吸附数据通过 Temkin 等温模型进行测试，R ＞0.97。根据热力学研究，吸附过程是吸热和自发的。总体而言，结果表明，所获得的复合材料可专门用于从水溶液中去除污染物。
