Adsorptive Removal\nof Cd(II) Ions from Water by a\nCheap Lignocellulosic Adsorbent and Its Reuse as a Catalyst for the\nDecontamination of Sulfamethoxazole

The work reports the removal of cadmium from water by\napplying\nan efficient low-cost lignocellulosic adsorbent, rooibos tea waste.\nThe cadmium-loaded rooibos tea waste was used for the photocatalytic\nabatement of sulfamethoxazole to cater to the setback of secondary\npollution mostly associated with the adsorption technique. The rooibos\ntea waste adsorbent displayed a high removal efficiency of about 90.63%\nfor 10 mg/L Cd(II) ions at 45 °C, 180 min agitation time, pH\n7, and a dosage of 500 mg. The process of Cd(II) adsorption was endothermic\nand spontaneous. Also, the spent adsorbent was found to be efficient\ntoward the photocatalytic breakdown of 10 mg/L sulfamethoxazole with\na degradation efficiency of 69% after 150 min. In addition, the extent\nof mineralization of the sulfamethoxazole by the spent adsorbent as\nobtained from the total organic carbon data was found to be 53%. Therefore,\nbased on the results obtained from this work, rooibos tea waste lends\nitself as a cheap, eco-friendly, easily sourced, and viable adsorbent\nfor the removal of toxic ions like Cd(II). Also, the successful reuse\nof the spent adsorbent is a promising approach to cater to the major\nsetback of secondary pollution associated with adsorption technology.