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 ΔG0 and the positive values of ΔH0 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.

中文翻译：

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孔雀石绿吸附在无花果叶上的平衡，动力学和热力学研究

染料从皮革，纸张和纺织品等濒临死亡的工业中释放出来是造成环境污染的重要原因。在本研究中，使用受刺激的水溶液进行批吸附测量，并研究了操作变量如初始孔雀石绿浓度，吸附剂数量，溶液pH，接触时间和溶液温度的影响。实验结果表明，去除率随初始染料浓度的增加而降低，但随着溶液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，Freundlich吸附等温线和Tempkin等温线模型分析了平衡数据，观察到朗缪尔吸附等温线更好地描述了吸附过程。用无花果叶制备的活性炭在298 K下对孔雀石绿的单层吸附能力为51.79 mg / g。此外，还研究了染料的吸附动力学，并发现吸附速率遵循拟假性。一阶动力学模型，其中粒子内扩散为速率确定步骤之一。ΔG0的负值和ΔH0的正值分别表示吸附过程的自发性和吸热性。在本研究中获得的实验结果以及与其他报道的吸附剂的比较表明，从无花果叶制备的活性炭可以用作低成本的替代吸附剂，用于从水溶液中去除孔雀石绿。