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• The types and challenges of PVC waste management are discussed. • Dehydrochlorination and dechlorination of PVC are reviewed. • Recent progress in the chemical recycling technologies of PVC is summarized. • The dechlorination principles of different technologies are explained. • Chemical recycling treatments of PVC-containing plastic waste are summarized. The extensive production and consumption of plastics has resulted in significant plastic waste and plastic pollution. Polyvinyl chloride (PVC) waste has a high chlorine content and is the primary source of chlorine in the plastic waste stream, potentially generating hazardous chlorinated organic pollutants if treated improperly. This review discusses PVC synthesis, applications, and the current types and challenges of PVC waste management. Dechlorination is vital for the chemical recycling of PVC waste and PVC-containing plastic waste. We review dehydrochlorination and dechlorination mechanisms of PVC using thermal degradation and wet treatments, and summarize the recent progress in chemical treatments and dechlorination principles. This review provides readers with a comprehensive analysis of chemical recycling technologies for PVC waste and PVC-containing plastic waste to transform them into chemicals, fuels, feedstock, and value-added polymers. [ABSTRACT FROM AUTHOR]

[Display omitted] • H 2 production of seaweed hydrolysate was studied with C. tyrobutyricum. • Acetate assimilation significantly promotes mannitol digestion and H 2 evolution. • Mannitol generates more reducing power for hydrogen evolution pathway. • Mannitol evolves 42.02% higher H 2 and 40.82% higher butyrate than glucose. • High H 2 yield (2.33 mol/mol) and energy recovery (41.20 %) were obtained from seaweed. In this study, mannitol and mannitol-rich seaweed were fermented to investigate the relationship between substrate reduction degree and hydrogen production performance. The results showed that acetate was required in mannitol fermentation with an optimum acetate/mannitol mass ratio of 1:5. Hydrogen production and yield of mannitol fermentation reached 123.76 mL and 2.12 mol/mol-mannitol, respectively, 42.02 % and 26.95 % higher than that of glucose, respectively. The acetate was fully assimilated and the butyrate selectivity reached 100 % in the effluent. Redox potential and electron distribution showed that mannitol increased the overall electron input from mannitol and acetate, leading to the increase in hydrogen and butyrate generation. Hydrogen yield reached 2.33 mol/mol-mannitol with brown algae hydrolysate, which was the highest ever reported. This study demonstrated that substrate with a higher reduction degree could yield higher hydrogen and showed the great application potential of brown algae fermentation for the co-production of hydrogen and butyrate. [ABSTRACT FROM AUTHOR]