Gebreslassie Yemane Tadesse
Department of Chemistry, Adigrat University, P.O. Box 50, Adigrat, Tigray, Ethiopia.
J Anal Methods Chem. 2020 Mar 4;2020:7384675. doi: 10.1155/2020/7384675. eCollection 2020.
The release of dyes from dying industries such as leather, paper, and textiles is an important cause of environmental pollution. In the present study, the batch adsorption measurements were carried out using stimulated aqueous solutions and the effect of operating variables such as initial malachite green concentration, amount of adsorbent, solution pH, contact time, and solution temperature, were investigated. The experimental result showed that the percentage removal decreased with an increase in initial dye concentration but increased as pH of the solution, contact time, and adsorbent dose increased. The equilibrium data were analyzed using Langmuir adsorption isotherm, Freundlich adsorption isotherm, and Tempkin isotherm models, and it was observed that the Langmuir adsorption isotherm better described the adsorption process. The monolayer adsorption capacity of activated carbon prepared from fig leaves for malachite green adsorption was found to be 51.79 mg/g at 298 K. Furthermore, the adsorption kinetics of the dye was investigated, and the rate of adsorption was found to follow the pseudo-first-order kinetic model with intraparticle diffusion as one of the rate-determining steps. The negative value of Δ and the positive values of Δ indicate the spontaneous and endothermic nature of the adsorption process, respectively. The experimental result obtained in the present study and comparison with other reported adsorbents indicate that activated carbon prepared from fig leaves could be used as a low-cost alternative adsorbent for the removal of malachite green from aqueous solution.
皮革、造纸和纺织等印染行业排放的染料是环境污染的一个重要原因。在本研究中，使用模拟水溶液进行了批量吸附测量，并研究了初始孔雀石绿浓度、吸附剂用量、溶液pH值、接触时间和溶液温度等操作变量的影响。实验结果表明，去除率百分比随初始染料浓度的增加而降低，但随溶液pH值、接触时间和吸附剂剂量的增加而增加。使用朗缪尔吸附等温线、弗伦德利希吸附等温线和坦普金等温线模型对平衡数据进行了分析，结果发现朗缪尔吸附等温线能更好地描述吸附过程。在298K下，由无花果叶制备的活性炭对孔雀石绿的单层吸附容量为51.79mg/g。此外，还研究了染料的吸附动力学，发现吸附速率遵循准一级动力学模型，颗粒内扩散是速率决定步骤之一。Δ的负值和Δ的正值分别表明吸附过程的自发性和吸热性。本研究获得的实验结果以及与其他报道的吸附剂的比较表明，由无花果叶制备的活性炭可作为一种低成本的替代吸附剂，用于从水溶液中去除孔雀石绿。
