Exploration of highly efficient and robust catalyst is pivotal for electrocatalytic degradation of dye wastewater, but it still is a challenge. Here, we develop a three-dimensional self-supported SnO₂-Mn₂O₃ hybrid nanosheets grown on carbon cloth (noted by SnO₂-Mn₂O₃@CC) electrode via a simple hydrothermal method and annealing treatment. Benefitting from the interlaced nanosheets architecture that enlarges the surface area and the synergetic component effect that accelerates the interfacial electronic transfer, SnO₂-Mn₂O₃@CC electrode exhibits a superior electrocatalytic degradation efficiency for cationic blue X-GRRL dye in comparison with the single metal oxide electrode containing SnO₂@CC and Mn₂O₃@CC. The degradation efficiency of cationic blue X-GRRL on SnO₂-Mn₂O₃@CC electrode can reach up to 97.55% within 50 min. Furthermore, self-supported architecture of nanosheets on carbon cloth framework contributes to a robust stability compared with the traditional electrode via the multiple dip/brush coating accompanied by the thermal decomposition method. SnO₂-Mn₂O₃@CC electrode exhibits excellent recyclability, which can still retain a degradation efficiency of 94.12% after six cycles. This work may provide a new pathway for the design and exploration of highly efficient and robust electrooxidation catalysts for dye degradation.

Industrial latex sludge as raw material was made into sulfonated latex sludge (SLS) and latex sludge active carbon (LSC) adsorbents by sulfonate and pyrolysis treatment to remove textile dye cationic blue X-GRRL from aqueous solution. The adsorption properties of SLS and LSC for X-GRRL were studied and compared by investigating the experimental parameters such as adsorbents dosage, pH, contact time and initial concentration. The kinetics of adsorption on SLS and LSC followed the pseudo-second-order kinetic model well. The adsorption isotherm and thermodynamic studies were further used to evaluate and compare the adsorption process of X-GRRL on SLS and LSC. The maximum adsorption capacities were 1219.6 mg/g for SLS and 476.2 mg/g for LSC according to the Langmuir model, respectively. These findings not only provide a sustainable strategy to turn industrial solid waste latex sludge into useful material for environment remediation, but also develop an efficient adsorbent for the treatment of dye wastewater.

Enhanced dewatering remains a major challenge in sludge disposal. In this paper, a thermal solidification treatment under low temperatures was first and successfully employed to improve the dewaterability of sludge from water-based ink wastewater. A total of 95.1% of dewatering ratio, 36.6% of moisture content, and 91.9% of sludge volume reduction could be acquired at 75 °C and 30 min setting time by the reported approach. The DSC results indicated that a large amount of bound water trapped in sludge could be released into the bulk solution to become free water after thermal solidification treatment. The bound water content of sludge can be reduced from 3.40 to 0.20 g g⁻¹ dry solid. The reported thermal solidification treatment is a thermophysical process that does not involve the solubilization of solid substrates and does not cause an increase in the COD value of dehydrated water. The obtained sludge after cooling was a clot of compacted cake with a uniform coralline-like structure. The softening and shrinking of acrylic resin within the sludge during heating contributed to the formation of compacted cake and thus enhanced the dewaterability. This study offers an economical and efficient treatment of sludge for the water-based ink printing industry.