A ubiquitous waste as a superior adsorbent for methylene blue removal: Cow-hair biochar

Abstract

The efficient and sustainable removal of organic dyes from wastewater remains a critical environmental challenge. In this study, cow hair, an abundant and underutilized agricultural waste, is transformed into biochar through a simple pyrolysis process to develop an effective and eco-friendly adsorbent for methylene blue (MB) dye removal. The physicochemical properties of the cow-hair biochar, including its surface area, porosity, and functional groups, were systematically analyzed to understand its adsorption performance. Batch adsorption experiments were conducted under varying conditions of pH, initial dye concentration, contact time, and pH to evaluate the adsorption efficiency of cow hair biochar. The results revealed that the biochar exhibits superior adsorption capacity for MB, driven by a combination of electrostatic interactions, π-π stacking, and surface oxygen functional group interactions. Using R2 as criteria, the best-fitting model was the Temkin isotherm, indicating a monolayer adsorption process with a maximum adsorption capacity surpassing many conventional adsorbents, achieving high levels of MB adsorption capacity of 730 mg/g. This study highlights the potential of converting cow hair waste into a high-performance adsorbent, offering a cost-effective and sustainable solution for dye-contaminated wastewater treatment. The findings pave the way for innovative waste valorization strategies and contribute to the advancement of green environmental technologies.