Centre of Excellence for Green Technologies, Department of Chemical and Environmental Engineering, Faculty of Engineering, The University of Nottingham Malaysia Campus, 43500 Semenyih, Selangor, Malaysia; Industrial Microwave Processing, Faculty of Engineering, The University of Nottingham, Nottingham NG7 2RD, UK.
Centre of Excellence for Green Technologies, Department of Chemical and Environmental Engineering, Faculty of Engineering, The University of Nottingham Malaysia Campus, 43500 Semenyih, Selangor, Malaysia.
J Environ Manage. 2015 Jul 1;157:320-5. doi: 10.1016/j.jenvman.2015.04.028. Epub 2015 May 2.
The production of natural biopolymers as flocculants for water treatment is highly desirable due to their inherent low toxicity and low environmental footprint. In this study, bio-flocculants were extracted from Hibiscus/Abelmoschus esculentus (okra) by using a water extraction method, and the extract yield and its performance in sludge dewatering were evaluated. Single factor experimental design was employed to obtain the optimum conditions for extraction temperature (25-90 °C), time (0.25-5 h), solvent loading (0.5-5 w/w) and agitation speed (0-225 rpm). Results showed that extraction yield was affected non-linearly by all experimental variables, whilst the sludge dewatering ability was only influenced by the temperature of the extraction process. The optimum extraction conditions were obtained at 70 °C, 2 h, solvent loading of 2.5 w/w and agitation at 200 rpm. Under the optimal conditions, the extract yield was 2.38%, which is comparable to the extraction of other polysaccharides (0.69-3.66%). The bio-flocculants displayed >98% removal of suspended solids and 68% water recovery during sludge dewatering, and were shown to be comparable with commercial polyacrylamide flocculants. This work shows that bio-flocculants could offer a feasible alternative to synthetic flocculants for water treatment and sludge dewatering applications, and can be extracted using only water as a solvent, minimising the environmental footprint of the extraction process.
由于天然生物聚合物具有固有低毒性和低环境足迹，因此将其作为水处理絮凝剂进行生产是非常理想的。在这项研究中，采用水提法从芙蓉/黄蜀葵（秋葵）中提取生物絮凝剂，并评估了其在污泥脱水方面的提取产率和性能。采用单因素实验设计，以获得最佳的提取条件，包括提取温度（25-90°C）、时间（0.25-5 小时）、溶剂负荷（0.5-5 w/w）和搅拌速度（0-225 rpm）。结果表明，提取产率受到所有实验变量的非线性影响，而污泥脱水能力仅受提取过程温度的影响。最佳提取条件为 70°C、2 小时、2.5 w/w 的溶剂负荷和 200 rpm 的搅拌速度。在最佳条件下，提取产率为 2.38%，与其他多糖（0.69-3.66%）的提取产率相当。生物絮凝剂在污泥脱水过程中对悬浮物的去除率>98%，水回收率为 68%，与商业聚丙烯酰胺絮凝剂相当。这项工作表明，生物絮凝剂可以为水处理和污泥脱水应用提供一种可行的替代合成絮凝剂的方法，并且仅使用水作为溶剂即可提取，从而最大限度地减少提取过程的环境足迹。
