The 9th International Conference on Water Resource and Environment (WRE 2023)

Abstract: The promotion of waste reutilization through environmentally friendly methods aligns with the principles of the circular economy. Embracing this, a deep understanding of surface chemistry becomes paramount in designing the optimal path for effective reutilization. In our study, we demonstrate our endeavours in repurposing waste beer dregs to degrade dye-contaminated wastewater and to recover fluoride using specialized cellulose filter papers. In the case of waste beer dreg reutilization, the initial step involved the conversion of waste beer dregs into biochar via high-temperature pyrolysis. To enhance the degradation of real dye-polluted wastewater, we introduced iron oxides onto the biochar surface through a hydrothermal reaction. While the degradation efficiency showed gradual decline across different operational batches, the catalysts exhibited remarkable rejuvenation potential through a straightforward carbothermal reaction. This innovative regeneration process empowered waste beer dregs to function as Fenton's reagent for effective dye wastewater degradation.
In a parallel effort, we functionalized cellulose filter papers using esterification. The introduction of associated carboxyl groups enabled the selective and efficient adsorption of calcium and magnesium cations from seawater. Subsequent reactions between the adsorbed calcium and magnesium and the fluoride ions facilitated the recovery of fluoride from wastewater. Notably, the porous nature of cellulose paper proved instrumental in retaining calcium and magnesium fluoride colloids, thus facilitating their separation from the wastewater. The cellulose paper containing calcium/magnesium fluorite emerged as a valuable green carbon source, finding utility in steel milling and cement production. This multifaceted approach not only highlights the potential economic gains but also presents the viability of effectively functionalizing waste for practical reutilization endeavors.