Ramutshatsha-Makhwedzha Denga, Mavhungu Avhafunani, Moropeng Mapula Lucey, Mbaya Richard
Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria West Campus, Private Bag X680, South Africa.
Heliyon. 2022 Jul 10;8(8):e09930. doi: 10.1016/j.heliyon.2022.e09930. eCollection 2022 Aug.
The study of adsorbent behaviour in laboratory conditions helps to predict the adsorption process in a large industrial scale. In this study, orange and lemon peels-derived activated carbon (OLPAC) was successfully synthesized and activated using phosphoric acid. Characterization was performed on the OLPAC and the material was used for the removal of methyl orange (MO) and methylene (MB) dyes from wastewater. The results of the scanning electron microscope and N adsorption/desorption examination affirmed that the prepared nanocomposite is permeable, which is an advantage for the efficient removal of contaminants. Optimal conditions for the batch removal process were investigated using a one-factor time approach in different conditions of adsorption (Dye concentration 50-200 mg L, pH 2-10, adsorbent mass 0.010-0.8, and contact time 5-180 min. The adsorption isotherm equilibrium data were examined by Langmuir, Freundlich, and Temkin, isotherm model. As shown by the correlation coefficient (R), the data were best described by Langmuir isotherms with maximum adsorption capacities of 33 and 38 mg g for methyl orange and methylene blue, respectively. Adsorption kinetic data were described using the pseudo-second-order model which suggests that adsorption of MO and MB was by chemisorption mechanism. The method was applicable to real wastewater samples, with satisfactory removal percentages of OM and MB (96 and 98 %). The results of this study show that OLPAC is an inexpensive biosorbent that is successfully utilized in removing methyl orange and methylene blue dyes from wastewater.
在实验室条件下对吸附剂行为进行研究有助于预测大规模工业生产中的吸附过程。在本研究中，成功合成了由橙皮和柠檬皮衍生的活性炭（OLPAC），并使用磷酸对其进行了活化。对OLPAC进行了表征，并将该材料用于去除废水中的甲基橙（MO）和亚甲基蓝（MB）染料。扫描电子显微镜和N吸附/解吸检测结果证实，所制备的纳米复合材料具有渗透性，这有利于高效去除污染物。采用单因素时间法在不同吸附条件下（染料浓度50 - 200 mg/L、pH值2 - 10、吸附剂质量0.010 - 0.8、接触时间5 - 180 min）研究了分批去除过程的最佳条件。通过Langmuir、Freundlich和Temkin等温线模型对吸附等温线平衡数据进行了考察。由相关系数（R）可知，数据最符合Langmuir等温线，甲基橙和亚甲基蓝的最大吸附容量分别为33和38 mg/g。吸附动力学数据采用准二级模型进行描述，这表明MO和MB的吸附是通过化学吸附机制进行的。该方法适用于实际废水样品，对OM和MB的去除率令人满意（分别为96%和98%）。本研究结果表明，OLPAC是一种廉价的生物吸附剂，可成功用于去除废水中的甲基橙和亚甲基蓝染料。
