Bio-removal of lead (II) ions under optimal condition by zinc chloride-impregnated activated carbon from brown alga

Sargassum sp., a brown alga in the division of macroalgae was evaluated for its ability to synthesis macroalgal-based activated carbon and remove lead (II) ions from synthetic aqueous solution. The sargassum activated carbon (SAC) was prepared by chemical activation impregnated with zinc chloride followed by carbonization. The surface morphology and functional group of untreated Sargassum sp. powder (SAP) and activated Sargassum sp. carbon (SAC) were scanned and presented with the Scanning Electron Microscope (SEM) and Fourier Transform Infrared spectroscopy (FTIR). Batch studies were conducted to explore maximum removal efficiency in term of pH, initial lead (II) ions concentration, contact time, adsorbent dosage, and temperature for the efficient adsorption. The maximum lead (II) ions uptake capacity for SAC was obtained at pH 5, initial lead (II) ions concentration at 25 mg/L, operation time of 60 min, adsorbent dosage of 0.1 g and temperature of 40 °C. The adsorption data were well-fitted by the Freundlich isotherm model, with an R² value of 1.000, indicating a good fit. The kinetic study revealed that the adsorption of lead (II) ions followed a pseudo-first-order kinetic model, with an R² value of 0.9746. This study validates the use of brown algae in the treatment of heavy metal contamination in wastewater.