Explore the Nano World 

Jul. 2022: Dr. Zhang’ group member, Shan Xue, delivered a poster at Gordon Research Conference on Nanoscale Science and Engineering for Agriculture and Food Systems.

Wen Zhang

Principal Investigator
Associate Professor

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

Office Location: Colton Hall 211

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Jul. 2022: Dr. Zhang’ group successfully co-organized and participated the CAPEES Workshop and Banquet events at AEESP in June 2022.

Following the previous paper on microplastics and BPA release from UV-aged plastic bottles, (https://doi.org/10.1021/acs.est.1c05812), Prof. Li Yang’s group at Beijing Normal University, recently published another paper (https://doi.org/10.1016/j.watres.2022.118320) in Water Research, which investigated the effects of surface coatings, polymer types and grain sizes on ROS generation and photoaging intermediates. Bare polystyrene (PS) NPs generated hydroxyl radicals (•OH) and singlet oxygen (1O2), while coated PS NPs (carboxyl-modified PS (PS-COOH), amino-modified PS (PS-NH2)) and PS MPs generated fewer ROS due to coating scavenging or size effects. Polypropylene, polyethylene, polyvinyl chloride, polyethylene terephthalate and polycarbonate MPs only generated •OH. For aromatic polymers, •OH addition preferentially occurred at benzene rings to form monohydroxy polymers. Excess •OH resulted in H abstraction, C-C scission and phenyl ring opening to generate aliphatic ketones, esters, aldehydes, and aromatic ketones. For coated PS NPs, •OH preferentially attacked the surface coatings to result in decarboxylation and deamination reactions. For aliphatic polymers, •OH attack resulted in the formation of carbonyl groups from peracid, aldehyde or ketone via H abstraction and C-C scission. Moreover, 1O2 might participate in phenyl ring opening for PS NPs and coating degradation for coated PS NPs. This study facilitates our understandings of the ROS-induced weathering process of NPs/MPs under UV irradiation.

ROS-mediated photoaging pathways of nano- and micro-plastic particles under UV irradiation

 Wen's Research Group​