Wen's Research Group​

Wen Zhang, Ph.D., P.E., BCEE

Principal Investigator

Phone: (973) 596-5520 
Fax: (973) 596-5790
Email: wen.zhang@njit.edu

Office Location: Colton Hall 211

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李莉莉:中国科学院水生生物研究所与新泽西理工学院联合培养博士生。主要研究方向为磁分离、混凝过滤等藻类收获技术及工程化应用。以第一作者在Journal of Cleaner Production, Separation and Purification Technology期刊发表论文4篇。 

Lili Li is a joint Ph.D. student at the Institute of Hydrobiology, Chinese Academy of Sciences, and the New Jersey Institute of Technology. Lili’s research focuses on algae harvesting technologies and their engineering applications, including magnetic separation and coagulation-filtration. She has published four first-author papers in journals such as the Journal of Cleaner Production and Separation and Purification Technology. 


Magnetic separation can swiftly remove many substances (e.g., biomolecules, cells, and viruses) from water. In algal bloom mitigation and biomass dehydration, magnetic particles (MPs) with proper surface modifications could effectively attract and remove algae from the impaired water body. It has long been expected to recover and reuse magnetic nanoparticles or particles to reduce the algal removal cost and potential adverse effects on the environment. This study evaluated the use of a tunable magnetic field to remove algae using functionalized MPs coated with polymers: polyethyleneimine (PEI), chitosan (CTS), and cetyltrimethyl ammonium bromide (CTAB), whose recovery and reuse were examined. The results show that PEI-coated MPs and CTS-coated MPs at the coating density of 2.3 g-cationic polymers·g-MPs-1 achieved higher removal efficiencies of 88.61 ± 9.12% and 73.19 ± 0.37%, respectively, toward a model algal cell (i.e., Scenedesmus obliquus) within a 5-min separation time. In contrast, CTAB-coated MPs and pristine MPs exhibited lower removal efficiencies (47.46 ± 0.3% and 52.69 ± 0.44%, respectively). Furthermore, the removal efficiency of PEI-coated MPs was further improved to over 95% under pH 7, the highest magnetic field of 40 mT, and algogenic organic matter-free conditions. Adsorption kinetics and isotherm analysis revealed that chemical and physical interactions drive the adsorption of a monolayer of algal cells on the surface of magnetic particles. Atomic force microscopy and quartz crystal microbalance confirmed a strong adhesion force and rate between functionalized MPs and algae, which affect both algal removal efficiency and MPs recovery from algae-MPs aggregates. The extended Derjaguin−Landau−Verwey−Overbeek (EDLVO) theory predicted a strong attractive force between algae and cationic polymer-coated MPs, which supported the enhanced algal removal. Finally, almost 99% of the four MPs could be recovered from separated algae-MPs aggregates within 30 s under the strong magnetic field and exhibited excellent magnetic responsiveness and reusability in further separation cycles. This study establishes a foundation for coagulant-free algae removal and enables the potential sustainable separation processes. 

A Chemical-Free Magnetophoretic Approach for Recovering Magnetic Particles in Microalgae Removal through Magnetic Separation 





论文link: https://doi.org/10.1016/j.jclepro.2024.143025 


中国科学院水生生物研究所张学治研究员课题组与新泽西理工学院张文教授课题组近期于Journal of Cleaner Production发表研究论文。 

磁分离可以迅速从水中去除多种物质,如生物分子、细胞和病毒。在藻华治理和生物质脱水过程中,通过适当表面改性的磁性颗粒(MPs)可以有效地吸附和去除受损水体中的藻细胞。长期以来,人们期望能够回收和重复利用磁性纳米颗粒,以降低藻细胞去除成本并减少对环境的潜在不利影响。本研究评估了在可调节磁场下,功能化聚合物包覆的磁颗粒(聚乙烯亚胺(PEI)、壳聚糖(CTS)和十六烷基三甲基溴化铵(CTAB))对藻细胞的直接去除性能,并检验了这些磁颗粒的回收和再利用效果。结果显示,PEI包覆的MPs和CTS包覆的MPs在涂层密度为2.3 g-阳离子聚合物·g-MPs-1时,在5分钟分离时间内对模式藻细胞(即斜生栅藻)的去除效率分别达到88.61 ± 9.12%和73.19 ± 0.37%。相比之下,CTAB包覆的MPs和原始MPs表现出较低的去除效率(分别为47.46 ± 0.3%和52.69 ± 0.44%)。此外,PEI包覆的MPs在pH 7、40 mT的高磁场强度和无藻源型有机物的条件下,去除效率进一步提高到95%以上。吸附动力学和等温线分析表明,化学和物理相互作用驱动了藻细胞在磁性颗粒表面的单层吸附。原子力显微镜和石英晶体微天平证实了功能化MPs与藻类之间的强粘附力和吸附速率。扩展的Derjaguin−Landau−Verwey−Overbeek (EDLVO)理论预测了藻细胞和阳离子聚合物包覆的MPs之间的强吸引力,支持了增强的藻细胞去除效果。最后,99%的MPs可以在30秒内从藻类-MPs聚集体中回收,并在进一步的分离循环中表现出优异的磁响应性和可重复使用性。本研究为无混凝剂的磁分离除藻奠定了基础,并为潜在的可持续分离过程提供了更多可能。 

A Chemical-Free Magnetophoretic Approach for Recovering Magnetic Particles in Microalgae Removal through Magnetic Separation 

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