Khan Abdul Ahad, Naqvi Salman Raza, Ali Imtiaz, Arshad Muazzam, AlMohamadi Hamad, Sikandar Umair
Laboratory of Alternative Fuels & Sustainability, School of Chemical & Materials Engineering, National University of Sciences & Technology, H-12, Islamabad, Pakistan.
Laboratory of Alternative Fuels & Sustainability, School of Chemical & Materials Engineering, National University of Sciences & Technology, H-12, Islamabad, Pakistan.
Chemosphere. 2023 Mar;316:137826. doi: 10.1016/j.chemosphere.2023.137826. Epub 2023 Jan 11.
Textile industries release effluent that contains the vast majority of heavy metals in which Cr (VI) is a toxic carcinogenic element that causes an environmental problem. The aim of the work is to synthesize algae-derived biochar derived from algae using slow pyrolysis at an operating temperature of 500 °C, a heating rate of 10 °C/min and a residence time of 60 min and to use it as an adsorbent to remove Cr (VI). The batch experiment was carried out using different concentrations of Cr (VI) (1, 10, 25, 50, 100, 125, 150 and 200 ppm) at different intervals of time (2.5, 5, 10, 15, 30, 60, 120 and 240 min). The maximum removal percentage of Cr (VI) is 97.88% for the metal concentration of 1 ppm exhibiting non-linear adsorption isotherm (Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin models) and kinetic models (pseudo-first order, pseudo-second order, nth order, and intra-particle diffusion) were analyzed using a solver add-in of Microsoft Excel. According to the results, the Langmuir isotherm model (R = 0.999) and pseudo-nth order models are suitable to describe monolayer adsorption and the process kinetics, respectively. The maximum adsorption capacity of algal biochar to adsorb is 186.94 mg/g. For the prediction of the optimal removal efficacy, an artificial neural network of the MLP-2-7-1 model was used. The results obtained are useful for future work using algal biochar as an adsorbent of Cr (VI) from textile wastewater to achieve sustainable development goals.
纺织工业排放的废水中含有绝大多数重金属，其中六价铬是一种有毒的致癌元素，会引发环境问题。这项工作的目的是在500℃的操作温度、10℃/分钟的加热速率和60分钟的停留时间下，通过慢速热解合成源自藻类的生物炭，并将其用作吸附剂来去除六价铬。分批实验在不同时间间隔（2.5、5、10、15、30、60、120和240分钟）使用不同浓度的六价铬（1、10、25、50、100、125、150和200 ppm）进行。对于1 ppm的金属浓度，六价铬的最大去除率为97.88%，呈现非线性吸附等温线（朗缪尔、弗伦德利希、杜比宁-拉杜舍维奇和坦金模型），并使用Microsoft Excel的求解器插件分析了动力学模型（伪一级、伪二级、n级和颗粒内扩散）。根据结果，朗缪尔等温线模型（R = 0.999）和伪n级模型分别适用于描述单层吸附和过程动力学。藻类生物炭的最大吸附容量为186.94 mg/g。为了预测最佳去除效果，使用了MLP-2-7-1模型的人工神经网络。所得结果对于未来将藻类生物炭用作纺织废水中六价铬的吸附剂以实现可持续发展目标的工作很有用。
