Utilization of Cuscuta japonica powder as a novel affordable adsorbent for removing disperse dyes from water

Abstract

Textile industrial activities have become major contributors of water pollution through the release of dyes into water systems. Disperse red 13 and disperse orange 3 dyes are still heavily used in the industry despite having been reported to be carcinogenic. Adsorption using locally available materials has recently emerged as an effective technology for the removal of pollutants from water. In this study, the potential of Cuscuta japonica powder was investigated for the removal of disperse red 13 and disperse orange 3 dyes from water. The C. japonica powder’s functional groups and the surface chemistry were examined using FTIR spectroscopy and SEM, respectively. TG-DTG analyses were employed to study the thermal characteristics of the powder while EDS was used to determine the elemental composition profile of the powder. Experiments were performed to determine the effect of contact time, pH, initial adsorbate concentration and reaction temperature on the removal of the two dyes from aqueous solution. After 120 min of reaction at 25 ℃, the removal efficiencies recorded were 87.77% and 79.16% for disperse red 13 and disperse orange 3, respectively. The corresponding sorption capacities were 11.10 mg/g for disperse red 13 and 10.61 mg/g for disperse orange 3. The adsorption of the two dyes onto the C. japonica powder followed the pseudo-second order kinetic model. This indicates that the adsorption of the two dyes is largely chemisorption. The Sips isothermal model provided the most appropriate fit for the two dyes. The adsorption of the two dyes onto the powder occur mainly through π–π stacking, hydrophobic interactions, and hydrogen bonding. The adsorption reaction of two dyes onto the adsorbent was exothermic and spontaneous. It was also established that the powder can be used more than three times without significantly losing its adsorptive capacity. These findings demonstrate that C. japonica vines can serve as an affordable source for adsorbent materials for the remediation of water polluted with industrial dyes.