Preparation of High-Performance CdS@C Catalyst Using Cd-Enriched Biochar Recycled From Plating Wastewater

Abstract

Biochar is widely used for the adsorptive removal of Cd from water and soil, but the Cd-enriched biochar produced carries a risk of secondary pollution. In this work, biochar derived from rice straw was used to adsorb Cd from plating wastewater. The Cd-enriched biochar showed a saturated adsorption capacity of about 63.5 mg/g and could be recycled and used in a mesoporous carbon-supported CdS (CdS@C) photocatalyst after pyrolysis carbonization and a hydrothermal reaction. The results demonstrated that the as-prepared CdS@C photocatalyst contained mixed cubic and hexagonal CdS phases, with a considerably lower band gap (2.1 eV) than pure CdS (2.6 eV). CdS@C exhibited an enhanced photocatalytic performance for the degradation of organic dyes under visible light irradiation compared with pure CdS due to its excellent light-harvesting capacity and efficient electron-hole separation. Moreover, the continuous formation of active species (h + , q OH, and O 2 q −) was responsible for the photodegradation of organic dyes using CdS@C. This work provides new insights for the safe disposal of Cd-enriched wastewater and for improving the economic viability of Cd-contaminated resources by recovering a value-added photocatalyst.

Coupling Plant Biomass Derived from Phytoremediation of Potential Toxic-Metal-Polluted Soils to Bioenergy Production and High-Value by-Products—A Review

“…Cd catalysts aimed for photodegradation of water pollutants down to permissible levels were prepared [42]. Xing et al [43] provided an alternative use of metal-contaminated streams when they demonstrated that vegetal biochar can be transformed with plating wastewater into reusable Cd-biochar acting as nano Cd-S with photocatalytic activities and tested the concept in dye removal from water.…”

The development of biomass-derived carbon-based photocatalysts for the visible-light-driven photodegradation of pollutants: a comprehensive review

“…Xing et al 128 utilized rice straw as a carbon source and Cd-containing plating wastewater as a Cd source to fabricate a CdS@C photocatalyst via facile pyrolysis carbonization and a hydrothermal process (see Fig. 13a ).…”

Mussel-Inspired Magnetic Dissolving Pulp Fibers Toward the Adsorption and Degradation of Organic Dyes

“…Adsorption is one of the most effective methods to treat organic dyes, and it is widely used because of its relatively low cost and easy operation. Various adsorbents have been designed to remove dyes in water and have considerable adsorption capacities, such as activated carbon ( Tang et al, 2017 ; Zhang et al, 2019 ; Soares et al, 2021 ), functional carbon materials ( Magno et al, 2020 ; Xing et al, 2020 ; Zhang et al, 2020 ), composite hydrogel ( Srivastava and Roy Choudhury, 2021 ), and metal oxide ( Rastogi et al, 2017 ; Xu et al, 2020 ; Şerban and Enesca, 2020 ). Among these methods, chemistry reduction has gained popularity because of its ease of use, high efficiency, clean processing, and low cost.…”