Supercritical water oxidation of polyvinyl alcohol and desizing wastewater： Influence of NaOH on the organic decomposition

• Published in: Journal of environmental sciences (China) Vol. 25; no. 8; pp. 1583 - 1591
• Main Authors: Zhang, Jie, Wang, Shuzhong, Guo, Yang, Xu, Donghai, Gong, Yanmeng, Tang, Xingying
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.08.2013
• Subjects: acetaldehyde; carbon; catalysis; chemical bonding; desizing wastewater; industry; NaOH; neutralization; organic acids and salts; Organic Chemicals - chemistry; oxidation; Oxidation-Reduction; polyvinyl alcohol; Polyvinyl Alcohol - chemistry; sodium hydroxide; Sodium Hydroxide - chemistry; supercritical water oxidation; Waste Water - chemistry; wastewater; Water - chemistry; Water Pollutants, Chemical - chemistry; water treatment; 俘获反应; 分解; 氢氧化钠; 聚乙烯醇溶液; 超临界水处理; 超临界水氧化; 退浆废水; catalysis; desizing wastewater; supercritical water oxidation; sodium hydroxide; polyvinyl alcohol
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/S1001-0742(9)60193-4

Polyvinyl alcohol is a refractory compound widely used in industry. Here we report supercritical water oxidation of polyvinyl alcohol solution and desizing wastewater with and without sodium hydroxide addition. However, it is difficult to implement complete degradation of organics even though polyvinyl alcohol can readily crack under supercritical water treatment. Sodium hydroxide had a significant catalytic effect during the supercritical water oxidation of polyvinyl alcohol. It appears that the OH ion participated in the C-C bond cleavage of polyvinyl alcohol molecules, the CO2-capture reaction and the neutralization of intermediate organic acids, promoting the overall reactions moving in the forward direction. Acetaldehyde was a typical intermediate product during reaction. For supercritical water oxidation of desizing wastewater, a high destruction rate （98.25%） based on total organic carbon was achieved. In addition, cases where initial wastewater was alkaline were favorable for supercritical water oxidation treatment, but salt precipitation and blockage issues arising during the process need to be taken into account seriously.