Valorizing Waste Bricks in Geopolymer Membrane Preparation for Treating Oily Wastewater: Effects of Curing Temperature and Liquid-to-Solid Ratio

The objective of this study is to explore the valorization potential of waste bricks through the preparation of geopolymer membranes. Specifically, we aim to investigate how curing temperatures and liquid-to-solid ratios influence the characteristics and performance of these geopolymer membranes, with a particular focus on their application in treating oily wastewater. After establishing the process for geopolymer membrane preparation, we characterized the membranes based on porosity, water absorption, contact angle, liquid entry pressure, and their efficiency in treating oily wastewater. The experimental results revealed that raising the curing temperature from 70 to 90 °C resulted in a significant 38% increase in porosity, leading to a 58% rise in water absorption. Additionally, the contact angle increased by 4%. Similarly, increasing the liquid-to-solid ratios from 0.4 to 0.5 led to a 39% increase in porosity, inducing a 22% and 8% rise in water absorption and contact angle, respectively. In the case of treating oily wastewater with an oil concentration of 125 mg L⁻¹, the geopolymer membrane cured at 80 °C with a liquid-to-solid ratio of 0.4 achieved an oil rejection rate of 89%.