CO2 capture performance of K2CO3-activated biochars derived from the textile dyeing sludge and corncob

Abstract

The advancement of low-cost biochar derived from organic solid wastes is highly desirable, as it serves as an efficient and environmentally friendly absorbent for CO2 abatement. Textile dyeing sludge (TDS) and corncob are two common types of carbonaceous solid wastes that are abundant and easily accessible. In this study, TDS and corncob were co-pyrolyzed to produce a series of CO2 adsorption biochars (SCs). Results show that the synergetic and self-catalytic effects of the reaction between alkali/alkaline earth metals and the organic matters in TDS and corncob can increase biochar yield and enhance the ultra-micropore structure accounting for effective CO2 adsorption. Moreover, the specific surface area of SC activated at 700 °C (SC700) was higher than corncob-based biochar. SC700 exhibited the highest CO2 adsorption capacity (128.1 mg/g) among the SCs, which was more than double that of TDS biochar. This is primarily because SC700 had the highest specific surface area of ultra-micropores (544.38 m2/g) and ultra-micropore volume (0.16 cm3/g) among the SCs. After ten cycles tests, SC700 still showed good CO2 adsorption-desorption performance, with a decrease of less than 1.5 %. The analysis of in situ DFIRT spectroscopy revealed that the CO2 adsorption of SC700 involved both physical and chemical adsorption processes, with physical adsorption being dominant. This study provides an environmentally friendly and cost-effective method for the utilization of TDS and corncob to produce valuable biochar for CO2 adsorption.

Keywords

• Textile dyeing sludge
• Ultra-micropores
• CO2 adsorption
• Synergetic effect
• Co-pyrolysis