Environ Technol. 2014 May-Jun;35(9-12):1077-90. doi: 10.1080/09593330.2013.861022.
The presence of dyes in effluent is a matter of concern due to their toxicologic and aesthetical effects. In this research, locally available agro-industrial wastes (Zea mays pericarp, ZMP; Agave tequilana bagasse, ATB; and Medicago sativa waste, MSW) were used as alternative low-cost adsorbents for the removal of methylene blue (MB) from aqueous solutions. The adsorbents were characterized physically and chemically by Fourier transform infrared, scanning electron microscopy, potentiometric titrations, and N2 physisorption. MB adsorption experiments were carried out in batch systems and experimental data were used to calculate the adsorption isotherm model parameters (Langmuir, Freundlich, and Temkin) and the adsorption kinetic model parameters (pseudo-first- and pseudo-second-order models). MB-loaded biosorbents were desorbed with deionized water, ethanol (10% and 50% v/v), hydrochloric acid (0.01 and 0.05 N), and sodium hydroxide (0.1 N) at room temperature, and the best eluent was used in various adsorption-desorption cycles. The selected agricultural wastes can be considered as promising adsorbents for dye uptake from water since they exhibit considerable MB adsorption capacity (MSW 202.6 mg g(-1), ATB 156.2mg g(-1), and ZMP 110.9mg g(-1)), but it is lower than that reported for activated carbon; however, the biosorbents show higher adsorption rate than powdered activated carbon. Furthermore, the adsorbents can be economically regenerated with HCl solutions and reused for seven adsorption-desorption cycles.
废水中染料的存在是一个令人关注的问题，因为它们具有毒理学和美学影响。在这项研究中，我们使用当地可得的农业工业废物（玉米皮、龙舌兰渣和三叶草废料）作为替代的低成本吸附剂，用于从水溶液中去除亚甲基蓝（MB）。吸附剂通过傅里叶变换红外光谱、扫描电子显微镜、电位滴定和 N2 物理吸附进行了物理和化学表征。在批量系统中进行了 MB 吸附实验，使用实验数据计算了吸附等温线模型参数（朗缪尔、弗伦德利希和特姆金）和吸附动力学模型参数（伪一级和伪二级模型）。用去离子水、乙醇（10%和 50%v/v）、盐酸（0.01 和 0.05N）和氢氧化钠（0.1N）在室温下对负载 MB 的生物吸附剂进行解吸，并在各种吸附-解吸循环中使用最佳洗脱剂。所选农业废物可以被认为是从水中摄取染料的有前途的吸附剂，因为它们具有相当大的 MB 吸附能力（三叶草废料 202.6mg g(-1)、龙舌兰渣 156.2mg g(-1)和玉米皮 110.9mg g(-1)），但低于活性炭的报道值；然而，生物吸附剂的吸附速率高于粉末活性炭。此外，吸附剂可以用 HCl 溶液经济地再生，并在七个吸附-解吸循环中重复使用。
