Document Type : Research Paper
Abstract
A major challenge in environmental remediation is the development of cost-effective processes that minimize the cost of energy and material while enabling the reuse of adsorbents for pollutant removal. Hydrochar (HC) is a promising substitute for biochar in environmental remediation, offering cost-effective, energy-efficient methods and enhanced regeneration through alginate immobilization. The adsorptive bahaviour of cobalt ions (Co2+) from wastewater on HC and hydrochar encapsulated in alginate (AHC) under different conditions and the physiochemical properties of the adsorbents were examined in this study. AHC had the highest Co2+ adsorption efficiency (100%), followed by AL (94.56%) and HC (91.31%). The adsorption ofCo2+ on HC and AHC was best fitted by the pseudo second order model, whereas the rate-determining steps were the Boyd diffusion and intraparticle diffusion models. The pseudo second order model provided the best fit for the adsorption ofCo2+ on HC and AHC, while the intraparticle diffusion and the Boyd diffusion models were the rate determining steps. At all temperatures considered (25, 30 and 36 oC), the Freundlich isotherm model provided the best fit for the experimental data and the maximum adsorption capacities at these temperatures ranged between 81.66 to 98.04 mg/g. AHC demonstrated superior adsorption performance due to improved active site accessibility and surface interactions. Given its high adsorption efficiency, reusability, and environmental compatibility, alginate-based hydrochar composites (AHC) are recommended as a viable material for practical heavy metal remediation in wastewater treatment
