Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, PR China.
Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, PR China.
J Hazard Mater. 2023 Apr 5;447:130795. doi: 10.1016/j.jhazmat.2023.130795. Epub 2023 Jan 14.
Solid-phase photocatalytic degradation of waste plastics is one of the promising approaches to solve the "white pollution" problem. In this work, a low cost, metal-free, environmentally friendly organic photocatalyst, graphite carbon nitride (g-CN), was used for the first time to successfully enhance the photodegradation of polyvinyl chloride (PVC) under simulated sunlight from its visible light photocatalytic capability, while its organic nature and abundant surface functional groups were beneficial for its good dispersion in plastics. It was found that the ultrathin porous g-CN nanosheet synthesized from urea (the UCN sample) had much stronger photodegradation effect in PVC/g-CN composite films than its thick block counterpart synthesized with melamine (the MCN sample) due to its larger specific surface area, higher pore volume, and enhanced photogenerated charge carrier separation. With the incorporation of only 1 wt% UCN sample into PVC, its mechanical properties were largely enhanced with the tensile strength increase of ∼ 45% and the elongation at break increase of ∼ 72%, and its weight loss increased ∼ 58% after 120 h irradiation in the weather resistance test chamber. O and h produced by the UCN sample were found as the main active species in the photocatalytic degradation of PVC to dechlorinate PVC and decompose its long-chain molecules into short-chain small molecules until its final degradation into CO and HO under ideal conditions.
固相光催化降解废塑料是解决“白色污染”问题的一种很有前途的方法。在这项工作中，首次使用了一种低成本、无金属、环保的有机光催化剂石墨相氮化碳（g-CN），利用其可见光光催化能力，成功地增强了聚氯乙烯（PVC）在模拟太阳光下的光降解，同时其有机性质和丰富的表面官能团有利于其在塑料中的良好分散。研究发现，与三聚氰胺合成的厚块状相比（MCN 样品），由尿素合成的超薄多孔 g-CN 纳米片（UCN 样品）在 PVC/g-CN 复合薄膜中具有更强的光降解效果，因为它具有更大的比表面积、更高的孔体积和增强的光生载流子分离。仅将 1wt%的 UCN 样品掺入 PVC 中，其力学性能得到了很大的提高，拉伸强度提高了约 45%，断裂伸长率提高了约 72%，在耐候性试验箱中照射 120 小时后，其失重增加了约 58%。在 PVC 的光催化降解过程中，UCN 样品产生的 O 和 h 被发现是主要的活性物质，它们可以脱氯降解 PVC，并将其长链分子分解成短链小分子，最终在理想条件下降解为 CO 和 HO。
