An environmental and green process for Pb⁺² pollution: An experimental research from the perspective of adsorption

Today, the increase in the need for quality and potable water resources is one of the most crucial issues that all countries of the world are focused on. Particularly, large amounts of highly polluted wastewater are formed together with water consumption that need to be treated in every sector. The toxic and harmful effects of pollutants such as lead still pose a challenge in terms of both environmental and human health in wastewater. Pb⁺² ion is an amphoteric, toxic and bioaccumulative type of primary pollutant commonly found in industrial wastewater. The adsorption process for Pb⁺² treatment is a basic method, and in recent years, adsorption studies have been carried out with various waste adsorbents from the aquatic system. Adsorption is considered the most widely used environmental and green process to remove heavy metal ions among the different processes. So, waste-based adsorbents that do not induce pollution have been evaluated. Therefore, unmodified tea waste, banana, almond, and eggshells were studied for the removal of Pb⁺² ions from the aqueous matrix. With the current process, Pb⁺² removal capacities were investigated by utilizing tea waste, banana, almonds, and eggshells in the aqueous solution. The effects of adsorbent concentrations (0.5-10 g), contact time (5-120 minutes), pH (2-12), and temperature (283.15-308.15 K) on removal efficiency of Pb⁺² were evaluated by batch mode adsorption experiments. Adsorption capacities were calculated using different isotherm and kinetic models due to the experimental datas. The maximum removal efficiencies of Pb⁺² were obtained as 89%, 93%, 98%, and 99% for the four adsorbents under optimum operating conditions respectively. Adsorption was fitted with Langmuir and pseudo-second-order kinetics at the equilibrium state. Experimental results showed that the selected adsorbents are environmentally friendly, economical, and easily obtainable for Pb⁺² removal compared to other adsorbent types.