Department of Mechanical Engineering, Iowa State University, Ames, IA, USA.
Department of Mechanical Engineering, Iowa State University, Ames, IA, USA.
Waste Manag. 2022 May 1;144:376-386. doi: 10.1016/j.wasman.2022.04.018. Epub 2022 Apr 19.
Polyvinyl chloride (PVC)-containing waste streams are difficult to recycle due to high chlorine content in PVC. Toxic dioxins or corrosive hydrogen chloride (HCl) vapor released from improper management of PVC-containing wastes can cause severe environmental pollution and human health problems. While PVC is usually treated as contamination and burden in waste recycling, a novel recycling approach was developed in this study to leverage PVC as an asset. Specifically, red oak and PVC were co-converted in γ-Valerolactone, a green biomass-derivable solvent. During the co-conversion, PVC-derived HCl in the solvent acted as an acid catalyst to produce up to 14.4% levoglucosenone and 14.3% furfural from red oak. On the other hand, dechlorinated PVC hydrocarbons and lignin fraction of red oak reacted each other to form chlorine-free solid fuels with high thermal stability. The higher heating value of the solids was up to 36.2 MJ/kg, which is even higher than the heating value of anthracite coal. After the co-conversion, more than 80% of PVC-contained chlorine turned into chloride ion and the rest formed 5-chlorovaleric acid. 5-chlorovaleric acid crystals were further recovered from the post-reaction liquid with a purity of 91.2%.
含聚氯乙烯（PVC）的废水因 PVC 中氯含量高而难以回收。含 PVC 废物管理不当释放的有毒二恶英或腐蚀性氯化氢（HCl）蒸气会造成严重的环境污染和人类健康问题。虽然 PVC 通常在废物回收中被视为污染物和负担，但本研究提出了一种新的回收方法，将 PVC 视为一种资产。具体来说，红橡木和 PVC 在γ-戊内酯（一种绿色生物质衍生溶剂）中进行共转化。在共转化过程中，溶剂中来自 PVC 的 HCl 充当酸催化剂，从红橡木中生成高达 14.4%的左旋葡酮和 14.3%的糠醛。另一方面，脱氯的 PVC 烃类和红橡木的木质素部分相互反应，形成具有高热稳定性的无氯固体燃料。固体的高热值高达 36.2 MJ/kg，甚至高于无烟煤的热值。共转化后，超过 80%的 PVC 所含氯转化为氯离子，其余部分形成 5-氯戊酸。后反应液中的 5-氯戊酸晶体进一步回收，纯度达到 91.2%。
