Adsorptive removal of acid blue 193 dye from wastewater using Citrullus colocynthis biomass

Due to their prevalence as contaminants in printing and textile industry wastewater, aqueous dyestuff decontamination approaches are receiving a lot of attention. Herein, the ability of powdered Citrullus colocynthis fruit peels (CCPs), a green agro-based adsorbent, to absorb an anionic acid blue 193 dye from an aqueous solution was further investigated. At pH 2.0 to 3.0, the monolayer adsorption capacity of CCP for the anionic dye species was 139.83 mg/g. Meanwhile, the successful dye uptake seen in the study is credited to the combined electrostatic interaction between the protonated adsorbent surface and the negatively charged sulfonic acid (–SO3H) group of the anionic acid blue 193 dye. Another potential adsorption mechanism is the creation of hydrogen bonds between the highly polar C = O and –OH groups of the adsorbent and the nitrogen atoms on the dye backbone. These findings suggest that CCP adsorbent is a viable candidate for the elimination of anionic acid blue 193 dyes from aqueous solution.