Jimoh Oluwatimileyin Samuel, Ibrahim Asiata Omotayo, Bello Olugbenga Solomon
Department of Pure and Applied Chemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria.
LAUTECH SDG 6, Ogbomoso, Oyo State, Nigeria (Clean Water and Sanitation Research Group).
Int J Phytoremediation. 2023;25(2):125-136. doi: 10.1080/15226514.2022.2064815. Epub 2022 May 20.
Acid modification of orange peels (OPAC); an agro-waste, using ortho-phosphoric acid was carried out. OPAC was characterized using FTIR and SEM, BET and elemental Analysis techniques respectively. It was then used for the adsorption of metformin (MET) from aqueous solutions. OPAC has different functional groups and prominent pore sizes suitable for the sorption of MET. Experimental parameters such as effects of contact time, MET initial concentrations, solution temperature and solution pH were investigated. Optimum MET adsorption onto OPAC was obtained at a contact time: of 240 minutes, Initial MET concentration: 5 mg/L, Temperature: 323 K, and pH 7. The highest percentage of MET removal using OPAC was 97.23%. Sorption data were fitted into four different isotherm models; Langmuir, Freundlich, Tempkin, and Dubinin-Radushkevich. Freundlich isotherm model best explained the sorption data with the high affinity of adsorption ( value) observed at 303 K. Langmuir isotherm gives an optimum monolayer sorption capacity of 50.99 mg/g at 323 K. Kinetic studies of the sorption process were investigated using pseudo-first-order, pseudo-second-order, Elovich, and Intraparticle diffusion kinetic models, and the data fitted best the pseudo-second-order kinetic model. Thermodynamic studies revealed that the sorption process is spontaneous, feasible, and endothermic. The energy of activation, suggests a physisorption mechanism of MET sorption onto OPAC. Conclusively, OPAC was an efficient adsorbent for the sorption of MET from aqueous solutions. Orange peel activated carbon (OPAC) adsorbent gave a higher value for metformin removal from aqueous solution than other adsorbents previously reported in the literature.The highest percentage of removal of metformin drug-using OPAC was 97.23%. This is highly commendable.
使用正磷酸对农业废弃物橙皮（OPAC）进行了酸改性。分别采用傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）、比表面积分析仪（BET）和元素分析技术对OPAC进行了表征。然后将其用于从水溶液中吸附二甲双胍（MET）。OPAC具有不同的官能团和适合吸附MET的显著孔径。研究了接触时间、MET初始浓度、溶液温度和溶液pH等实验参数的影响。在接触时间为240分钟、初始MET浓度为5mg/L、温度为323K和pH为7的条件下，OPAC对MET的吸附达到最佳效果。使用OPAC去除MET的最高百分比为97.23%。吸附数据拟合到四种不同的等温线模型；朗缪尔（Langmuir）、弗伦德利希（Freundlich）、坦普金（Tempkin）和杜比宁-拉杜舍维奇（Dubinin-Radushkevich）。弗伦德利希等温线模型最能解释吸附数据，在303K时观察到具有高吸附亲和力（值）。朗缪尔等温线在323K时给出的最佳单层吸附容量为50.99mg/g。使用伪一级、伪二级、埃洛维奇（Elovich）和颗粒内扩散动力学模型对吸附过程进行了动力学研究，数据最符合伪二级动力学模型。热力学研究表明，吸附过程是自发的、可行的且吸热的。活化能表明MET吸附到OPAC上的物理吸附机制。总之，OPAC是从水溶液中吸附MET的有效吸附剂。橙皮活性炭（OPAC）吸附剂从水溶液中去除二甲双胍的值高于文献中先前报道的其他吸附剂。使用OPAC去除二甲双胍药物的最高百分比为97.23%。这非常值得称赞。
