Department of Environmental Sciences, University of Peshawar, Peshawar 25120, Pakistan.
Institute of Chemical Sciences, University of Peshawar, Peshawar 25120, Pakistan.
Water Sci Technol. 2021 Aug;84(3):609-631. doi: 10.2166/wst.2021.252.
Serious environmental deterioration caused by synthetic waste plastics, and the pollution of freshwater resources are the most alarming and marked challenges of the 21st century. Therefore, immense scientific efforts are being made towards the management of waste plastics and treatment of polluted water. The current study reports on the utilization of waste polyethylene terephthalate (wPET) and waste polystyrene (wPS) for fabrication of activated carbon (AC) and its application for the removal of hazardous polycyclic aromatic hydrocarbons (PAHs) pollutants from water. AC was prepared from wPET and wPS by carbonization under a N atmosphere followed by chemical activation with 1 M KOH and 1 M HCl. The AC was characterized by scanning electron microscopy, surface area analysis, and Fourier transform infrared spectroscopy. Adsorption of PAHs from aqueous solutions through AC was examined by batch adsorption tests. The optimum parameters for maximum adsorption of PAHs were found to be: initial PAHs concentration 40 ppm, 2 h contact time, pH 3, 5, and 7, 50 °C temperature and adsorbent dose of 0.8 g. Kinetic and isotherm models were applied to evaluate the adsorbent capacity for PAHs adsorption. The kinetic study shows that the adsorption of these PAHs onto AC follows pseudo-second-order kinetics. The experimental results demonstrated that the Langmuir isotherm model best fitted the data. The thermodynamic factors calculated such as entropy change (ΔS°), enthalpy change (ΔS°) and free energy change (ΔG°) show that the adsorption process is non-spontaneous and endothermic in nature. Results were also compared with the efficiencies of some commercial adsorbents used in practice. This examination revealed that the novel plastic-derived AC possesses a great potential for elimination and recovery of PAH elimination from industrial wastewater.
合成废塑料造成的严重环境恶化和淡水资源污染是 21 世纪最令人震惊和显著的挑战。因此，人们正在进行大量的科学努力来管理废塑料和处理受污染的水。本研究报告了利用废聚酯（wPET）和废聚苯乙烯（wPS）制备活性炭（AC）及其在去除水中危险多环芳烃（PAHs）污染物方面的应用。AC 是通过在 N 气氛下碳化，然后用 1 M KOH 和 1 M HCl 化学活化制备的。通过扫描电子显微镜、比表面积分析和傅里叶变换红外光谱对 AC 进行了表征。通过批量吸附试验考察了 AC 从水溶液中吸附 PAHs 的情况。发现最大吸附 PAHs 的最佳参数为：初始 PAHs 浓度 40 ppm、接触时间 2 h、pH 值为 3、5 和 7、温度为 50°C 和吸附剂剂量为 0.8 g。动力学和等温线模型被应用于评价吸附剂对 PAHs 吸附的容量。动力学研究表明，这些 PAHs 吸附到 AC 上遵循准二级动力学。实验结果表明，Langmuir 等温线模型最适合该数据。计算得出的热力学因素，如熵变化（ΔS°）、焓变化（ΔH°）和自由能变化（ΔG°）表明，吸附过程是非自发的和吸热的。结果还与一些实际应用中的商业吸附剂的效率进行了比较。该研究表明，新型塑料衍生的 AC 具有从工业废水中去除和回收 PAH 的巨大潜力。
