Abstract:
Malachite green (MG) dye and cadmium metal ion are toxic pollutants that should be removed from aqueous environment. The recent study aimed to examine the adsorption behavior of MG dye and Cd (II) from wastewater onto low-cost adsorbent prepared by activating corn silk with nitric acid (ACS) and characterized by SEM, FTIR, XRD, BET and TGA. The optimum MG and Cd (II) adsorption was observed at pH 7 and pH 9 and maximum uptake of both pollutants was at 0.5 g dosage, 60 mins contact time and 20 mg/L initial concentration. The retention of dye and metal ion by the studied adsorbent was best fit to Langmuir isotherm and Pseudo-second order kinetics. The maximum monolayer coverage capacity of ACS for MG dye and Cd (II) ion was 18.38 mg/g and 25.53 mg/g, respectively. Thermodynamic studies predicted a spontaneous reaction with exothermic process for MG dye whereas an endothermic and spontaneous process was confirmed for Cd ion based on estimated parameters. The adsorption mechanism of MG dye and Cd (II) uptake was by combination of electrostatic interaction, pore diffusion, ion exchange, pie-pie attraction, hydrogen bonding, and complexation. The adsorbed pollutants were effectively desorbed with significant regeneration efficiency after successive five cycles that proved the potential of low-cost biosorbent for selective sequestration of cationic dye and divalent metal ion from effluents.
The use of nitric acid-modified corn silk has been reported to enhance its adsorption performance over the unmodified cob for pollutants such as cadmium ions and malachite green. Although there may be no recorded data on the adsorption efficiency of acid-treated corn silk for selected pollutants, it can be considered as a prospective bio-sorbent owing to its chemical composition and functional groups for exchange of hydrogen ions for other cations.
摘要:
孔雀石绿(MG)染料和镉金属离子是有毒污染物,应从水性环境中去除。最近的研究旨在研究废水中MG染料和Cd(II)在低成本吸附剂上的吸附行为,该吸附剂是通过硝酸(ACS)活化玉米丝制备的,并通过SEM进行了表征。FTIR,XRD,BET和TGA。在pH7和pH9下观察到最佳的MG和Cd(II)吸附,两种污染物的最大吸收均为0.5g。60分钟接触时间和20mg/L初始浓度。所研究的吸附剂对染料和金属离子的保留最符合朗缪尔等温线和伪二级动力学。ACS对MG染料和Cd(II)离子的最大单层覆盖能力分别为18.38mg/g和25.53mg/g,分别。热力学研究预测了MG染料的放热过程的自发反应,而根据估计的参数确认了Cd离子的吸热和自发过程。MG染料和Cd(II)吸收的吸附机理是通过静电相互作用,孔隙扩散,离子交换,馅饼的吸引力,氢键,和复合。连续五个循环后,吸附的污染物以显着的再生效率被有效解吸,这证明了低成本生物吸附剂从废水中选择性螯合阳离子染料和二价金属离子的潜力。
据报道,与未改性的玉米芯相比,使用硝酸改性的玉米丝可以增强其对镉离子和孔雀石绿等污染物的吸附性能。尽管可能没有关于酸处理过的玉米丝对选定污染物的吸附效率的记录数据,由于其化学组成和氢离子与其他阳离子交换的官能团,它可以被认为是一种有前景的生物吸附剂。