Alobaidi Daad Saad, Alwared Abeer I
Ministry of Youth and Sports, Iraq.
Department of Environmental Engineering/College of Engineering/University of Baghdad, Iraq.
Heliyon. 2023 Mar 25;9(4):e14851. doi: 10.1016/j.heliyon.2023.e14851. eCollection 2023 Apr.
In this work, sodium alginate-immobilised Chlorophyta algae were evaluated for phenol uptake. The algae/alginate bead (AAB) characteristics were analysed by means of BET-BJH, FTIR, and SEM-EDX methods, while the adsorption performance of AABs with respect to phenol removal was investigated using batch studies. The parameters found to affect the biosorption capacity of AABs included pH, contact time, initial phenol concentration, adsorbent dosage, stirring rate, particle size, and temperature, with the optimal operating variables identified as a pH of 6, an initial phenol concentration of 50 mg/L, AAB dosage of 5 g/L, and a 200 rpm stirring rate. The adsorption process in such cases reached equilibrium within 120 min, demonstrating a maximum phenol elimination capacity of 9.56 mg/g at 30 °C. The isotherm and kinetic models used to determine this were evaluated using the Chi-square test (X), the coefficient of determination (R), and the value of equilibrium capacity, with results that revealed that the Freundlich isotherm provides the best fit for the relevant equilibrium data, as shown by its high R value (0.96) and low X value (1.16135); the theoretical data produced by that model were thus closer to the experimental data than that from the Langmuir model. Kinetic analysis showed that the phenol adsorption followed a pseudo-second-order kinetic model. The thermodynamic parameters were thus explored, revealing that the phenol biosorption process is based on spontaneous physisorption with an exothermic reaction due to negative (ΔG°) and (ΔH°) values. The low cost, natural origin, biodegradability, and eco-friendliness of algae/alginate bead sorbents also make them ideally suited for phenol removal in aqueous solutions.
在本研究中，对海藻酸钠固定化绿藻吸收苯酚的性能进行了评估。通过BET-BJH、傅里叶变换红外光谱（FTIR）和扫描电子显微镜-能谱分析（SEM-EDX）方法对藻/藻酸盐珠（AAB）的特性进行了分析，同时采用批次研究法考察了AAB对苯酚的去除吸附性能。发现影响AAB生物吸附容量的参数包括pH值、接触时间、初始苯酚浓度、吸附剂用量、搅拌速率、粒径和温度，确定的最佳操作变量为pH值6、初始苯酚浓度50 mg/L、AAB用量5 g/L和搅拌速率200 rpm。在这种情况下，吸附过程在120分钟内达到平衡，在30℃时苯酚的最大去除容量为9.56 mg/g。用于确定此结果的等温线和动力学模型通过卡方检验（X）、决定系数（R）和平衡容量值进行评估，结果表明Freundlich等温线最适合相关平衡数据，其高R值（0.96）和低X值（1.16135）表明了这一点；因此，该模型产生的理论数据比Langmuir模型的数据更接近实验数据。动力学分析表明，苯酚吸附遵循准二级动力学模型。由此对热力学参数进行了探索，结果表明苯酚生物吸附过程基于自发的物理吸附，由于负的（ΔG°）和（ΔH°）值而发生放热反应。藻/藻酸盐珠吸附剂的低成本、天然来源、可生物降解性和生态友好性也使其非常适合去除水溶液中的苯酚。
