Modification of low-cost adsorbent prepared from agricultural solid waste for the adsorption and desorption of cationic dye

This study focused on the adsorption in an aqueous solution of methylene blue (MB) cationic dye used in the textile industry by the almond shell (AS) using sodium hydroxide (NaOH). The removal process was optimized by employing different parameters like AMAS dosage, reaction time, MB concentration, and pH of the solution. At optimum conditions (AMAS dose =1.6 g L-1, time = 20 min, MB concentration =100 mg L-1, T = 22 +/- 1 degrees C, and pH = 5.57), the MB removal was found to be 96.13%. This study also reported the MB desorption from MB-AMAS using nitric acid (HNO3) as a desorbing agent. The influence of MB-biomaterial dose, contact time, and HNO3 solution concentration on MB desorption was experimentally determined by batch tests. The MB desorption efficiency was 98.29% using 0.1 M of HNO3 solution. The expression of the pseudo-second-order model best describes the kinetic adsorption results. The maximum adsorption capacity of AMAS was 104.31 mg g(-1). The AMAS could be regenerated and reused for six consecutive cycles. The result obtained suggests that the adsorbent developed from the almond shell by NaOH modification has promising potential for dye removal from wastewater and are an ideal alternative to conventional approaches.

Automated summary

This study focused on the adsorption and desorption of methylene blue dye using almond shell modified with sodium hydroxide. The results showed that the modified almond shell has promising potential for dye removal and can be regenerated for reuse.