Catalytic hydrothermal treatment of pulping effluent using a mixture of Cu and Mn metals supported on activated carbon as catalyst

Abstract

The present study was performed to investigate the performance of activated carbon-supported copper and manganese base catalyst for catalytic wet oxidation (CWO) of pulping effluent. CWO reaction was performed in a high pressure reactor (capacity = 0.7 l) at temperatures ranging from 120 to 190 °C and oxygen partial pressures of 0.5 to 0.9 MPa with the catalyst concentration of 3 g/l for 3 h duration. With Cu/Mn/AC catalyst at 190 °C temperature and 0.9 MPa oxygen partial pressures, the maximum chemical oxygen demand (COD), total organic carbon (TOC), lignin, and color removals of 73, 71, 86, and 85 %, respectively, were achieved compared to only 52, 51, 53, and 54 % removals during the non-catalytic process. Biodegradability (in terms of 5-day biochemical oxygen demand (BOD) to COD ratio) of the pulping effluent was improved to 0.38 from an initial value of 0.16 after the catalytic reaction. The adsorbed carbonaceous fraction on the used catalyst was also determined which contributed meager TOC reduction of 3-4 %. The leaching test showed dissolution of the metals (i.e., Cu and Mn) from the catalysts in the wastewater during CWO reaction at 190 °C temperature and 0.9 MPa oxygen partial pressures. In the future, the investigations should focus on the catalyst reusability.

Performance of Supported Copper Catalysts for Oxidative Degradation of Phenolics in Aqueous Medium: Optimization of Reaction Conditions, Kinetics, Catalyst Stability, Characterization, and Reusability

“…Several research studies on WO and CWO of the synthetic wastewaters containing model compounds like phenols, − ferulic acid (a lignin model compound), − and carboxylic acids have been reported in the literature. Moreover, simulated and real industrial effluents have also been treated by noncatalytic and catalytic hydrothermal oxidative processes. − …”

Performance assessment of activated carbon supported catalyst during catalytic wet oxidation of simulated pulping effluents generated from wood and bagasse based pulp and paper mills

“…In our research group, several studies have been performed on the treatment of synthetic as well as simulated pulping effluent using CWO process. [10][11][12][13][14][15] In these studies, the performance of mono and bimetallic supported catalysts was explored. Copper and manganese have been used as active metal species while activated carbon (AC), alumina (Al 2 O 3 ) and ceria were used as the catalyst support.…”