Mespilus germanica (MG) and Tribulus terrestris (TT) Used as Biosorbents for Lead Removal from Aqueous Solutions: Adsorption Kinetics and Mechanisms

Today, most countries around the globe are facing water resources restrictions, and it is predicted freshwater resources will be more valuable than oil wells in the next century. In the present study, the ability of lead removal using both powders of Mespilus germanica (MG) and Tribulus terrestris (TT) seeds and optimization of the adsorption process have been investigated. Four main parameters were selected for experimental design, namely, pH, time of contact, the ratio of adsorbent to solution volume, and initial concentration of lead in solution, and the optimization of effective parameters on lead adsorption was performed based on central composite design (CCD) under response surface methodology (RSM). According to the statistical results, the proposed model for MG and TT is confirmed with 0.95 and 0.96 correlation coefficient and 0.92 and 0.94 adjusted correlation coefficient, respectively. The results of parameter optimization also showed that both adsorbents have the acceptable ability to adsorb lead from aqueous solutions. Under the optimum conditions with the initial lead concentration of 10 mg/l, MG powder had better performance in lead adsorption of 96.04%, and TT powder also had an acceptive performance of 93.20%. Moreover, the MG and TT adsorbents have the most accordance with the Freundlich and D-R isotherms, respectively.

Study of Green Seaweed Biochar for Lead Adsorption from Aqueous Solution

The current work used a batch study to investigate the efficiency of Ulva lactuca carbon for lead adsorption from aqueous solution. For the optimization study, the effects of several parameters such as pH, Adsorbent dosage, effective contact time, and initial concentration on lead removal were also considered. pH 3 was observed to be the most beneficial. The Langmuir isotherm, which represents mono-layer adsorption, yielded a maximum lead absorption of 3.49 mg/g. SEM was used to examine surface adsorption behavior, and FTIR was used to detect probable functional groups involved in the bio-adsorption experiment. This study shows that biochar made from the marine algae Ulva lactuca is effective for waste water treatment.

Removal of Lead Ions from Water Using Pellet Generated from Bacillus subtilis Isolated from Gold Mining Site in Niger State

This work concentrated on the isolation of lead tolerant strains of bacteria, identification of the isolated strain with the highest lead tolerance capacity using microgen identification kit. Also, the efficacy of the generated pellet (dead cell) in the bioremoval of lead from aqueous solutions was determined. A total of nine bacteria were isolated from soil collected from gold mining site in Kontagora metropolis, Niger State. Of the nine isolates, only Bacillus subtilis (KO1) possess high tolerance capacity for high levels of lead ions. The pellet generated from the Bacillus subtilis (KO1) strain was then used to adsorb lead ions from synthetic ion solutions. The isolate's removal efficiency was enhanced by optimizing several physical conditions (pH, temperature, initial lead concentration and contact time). The best optimized adsorption removal efficiency (>90%) was found at pH 3, temperature 40oC with 100 mg/L of initial concentration of lead after 3 hours of treatment. The use of the pellet generated from eco-friendly Bacillus subtilis (KO1) has great potential and additional benefits in terms of lead removal. Keywords: Bacillus subtilis; lead; adsorption; pellet; optimization