Innovative Biochar-Infused Membranes for Efficient Pollutant Removal From Textile and Pharmaceutical Wastewater

In this study, biochar infused polymeric mixed matrix are prepared by spin-coating technique for the adsorption of certain dye and antibiotic pollutants from wastewater samples. This method could potentially be economic in comparison to the classical methods for wastewater treatment. The adsorbent biochar infused in the MMMs is derived from pyrolysis of industrial spice waste (SW) and tannery waste (TW) at 500°C rather than pyrolysis of expensive virgin materials. After the characterization studies (proximate analysis, FESEM, BET, point of zero charge, and XRF) on the biochar and the membrane samples, the adsorption studies are carried out on Congo red (CR), methylene blue (MB) and tartrazine (Tz) dye, and metronidazole (Mz) and clindamycin hydrochloride (CH). It is found that SW biochar does not show any affinity towards antibiotics pollutant whereas TW biochar can adsorb dyes and antibiotics both. Membrane filtration exhibits slightly lower adsorption efficiency compared with batch adsorption using biochars alone; however, it offers faster processing and the advantage of continuous operation. For the optimization study, the initial concentration and pH of the solution were varied between 50-150 mg/L and pH 4-10, respectively. Maximum removal efficiencies of 60%, 83%, 58%, 47%, and 58% were achieved for CR, MB, Tz, Mz, and CH, respectively, at their optimized concentrations and pH conditions. Additionally, regeneration and reusability studies indicate that the membranes can be effectively regenerated by simple washing with distilled water and reused for up to five adsorption cycles. SUMMARY: Biochar infused membranes are produced using spin coater using spice waste and tannery waste. Surface area increases when biochar is infused with polymer to prepare membrane. Spice waste-based membranes show removal of methylene blue and Congo red dyes only. Tannery waste-based membranes can adsorb methylene blue, Congo red, metronidazole, and clindamycin.