Evaluation on the Zn2+ ion adsorption capacity in water of Spirulina platensis biomaterial

Abstract

Due to its rising accumulation in the food chain and ongoing presence in ecosystems, metal contamination has piqued the curiosity of experts from all over the world.Environmentallyhazardous heavy metal removal is being pursued utilizing a variety of techniques, such as ion exchange and precipitation, as well as chemical oxidation or reduction, electrochemistry,and filtration. However, these methods require high investment and operating costs,and generate toxic sludge.Spirulina platensis, a filamentous cyanobacteria species, has been reported as a potential bioadsorbent for the removal of some heavy metals from industrial wastewater. In this study, the bioadsorption of Zn2+ionsin anassumedaqueous solution by the dry biomass of S. platensisTHwas investigated. The Zn2+ion adsorption of biomaterials was evaluated under different conditions,including pH, contact time, temperature,and adsorbent mass. The optimal Zn2+ ion removal efficiency reached 90.32 ± 0.29% at Zn2+ ion concentrationof100 mg/L, pH 5.0, a temperatureof26oC,and adry biomass doseof1.5 g/L for 90 min. Langmuir and Freundlich's isothermal modelswereused to describe the adsorption isotherm of Zn2+ions onS. platensisTH. Equilibrium data fitted well with the Langmuir model as well as the Freundlich model,with a maximum adsorption capacity of 34.56 mg Zn2+/gS. platensisTHunder the reaction conditions of 1.5 g/Lbiomass dosage, the contact time of 90 min, pH 5.0, at26oC. Research results have shown that S. platensisTHbiomass is an easy, readily available, low-cost adsorbent and has a high bioadsorption capacity.Therefore, it can be treated as a bioadsorbent in the treatment of wastewater containing Zn2+ions. This process is not onlyenvironmentallyfriendly but also versatile as an alternative to conventional heavy metal treatmentmethods.