A critical review focusing on the production and application of GO-CNC-based nanosorbents in wastewater treatment: Removal of toxicants by fixed bed column adsorption study.

内容摘要

Approximately 80% of the hundreds of billions of cubic meters of wastewater produced annually worldwide is released into the environment untreated, representing a global environmental and public health challenge that needs urgent deployment of advanced nanosorbents. Among all the treatment methods, adsorption is a scalable, low-cost, environmentally friendly method for treating wastewater. Graphene oxide (GO) and cellulose nanocrystals (CNC) are some of the most researched advanced nanosorbents. Both GO and CNC together form a porous, oxygen-rich matrix and carbonaceous active materials along with a substantial amount of binding/receptor sites that overcome individual precursor limitations, showing synergistic effects of electrostatic attraction, hydrogen bonding, and π-π stacking altogether to remove toxicants from industrial wastewater bodies at such efficiencies that neither precursor could do individually. Detailed preparation of precursors, fifteen fabrication routes, fourteen characterization techniques, effects of flow rate, bed height, pH, and GO: CNC ratio on breakthrough behavior, different column adsorption models, and a comparative study between GO-CNC-based adsorbents are provided. This review also deals with challenges: multi-pollutant selectivity, regeneration limits, and reactor scalability. Renewable biomass feedstocks, spent-sorbent reuse in supercapacitors and construction, and a zero-waste path across eleven UN SDGs are mentioned as a future pathway for environmental sustainability, and eco-industrial as well as technological developments.