Investigating the Efficacy of Aloe Vera Powder Modified with Sulfuric Acid in Removing Bisphenol A from Aqueous Solutions

Phenol is one of the organic pollutants in industrial effluents and is highly toxic to humans and the environment, so it must be treated before being discharged into the environment. The aim of this study was the comparative investigation of the performance of aloe vera powder modified with sulfuric acid in removing bisphenol A from aqueous solutions.

This research was performed in a laboratory method in batch system. First, aloe vera was prepared and its leaves were washed several times with distilled water to remove impurities. It was dried in the oven at 120  for 24 h and was sieved  with standard ASTM 50 mesh. Changes in pH (3-11), adsorbent dosage (1-5 g/L), contact time (10-90 min) and bisphenol A concentration (10-50 mg / L) were investigated. Optimization of experiments and data analysis in the adsorption process to eliminate base phenol A was performed using central composite design (CCD).

The results showed that the adsorption rate of phenolic compound increases with increasing contact time and adsorption dose. The maximum adsorption of bisphenol A was obtained at pH of 3 and the initial bisphenol A concentration of 10 mg/L. Based on the analysis of variance of test results from different models, the second-order (Quadratic) model was selected to estimate the removal of bis phenol A by the adsorption process using the modified adsorbent. The linear regression coefficient (R2) between the experiments and the different values ​​of the response in the model was 0.96. The optimal value for the studied variables included pH of 6, adsorbent dose of 4.2 g/L, contact time of 65 min and bis phenol A concentration of 40 mg/L. Under these conditions, the efficiency of BPA removal was 87.06%.

The results showed that the adsorption process using the modified adsorbent is able to remove the bisphenol A with relatively high efficiency. This method can also be used to treat wastewater from oil and petrochemical industries containing phenolic compounds.