Solar water evaporation using porous cellulose polyacrylamide hydrogel with carbon-based material containing copper oxide prepared from after-use adsorbent

The global printed circuit board (PCB) industry produces millions of tons of wastewater containing Cu2+ every year, which exacerbates the shortage of freshwater. As one of low cost, eco-friendly and effective materials, the chitosan-based adsorbent has been widely used for the disposition of PCB industrial sewage. Unfortunately, little attention is paid to the reutilization of waste adsorbent. In this work, we synthesized a carbon-based material containing copper oxide (CMCC) by calcining a chitosan porous adsorption material (CPAM) with Cu2+ as the after-use adsorbent. Then, by loading the CMCC as the photothermal conversion material, a flexible porous cellulose polyacrylamide hydrogel (PCPH) was fabricated, whose light absorbance was 97.4%. Moreover, the PCPH achieved a prominent evaporation rate of 1.80 kg m−2 h−1 under the light intensity of 1.0 kW m−2. In addition, the PCPH possessed superb stability and the desalinated seawater successfully reached the criterion of drinking water from the World Health Organization (WHO). The results revealed that the PCPH with CMCC for solar water evaporation is a possible solution to the reuse of waste adsorbent from PCB industry and the competent remission of freshwater shortage.