Potential of Capparis decidua plant and eggshell composite adsorbent for effective removal of anionic dyes from aqueous medium.

The presence of hazardous dyes in wastewater poses significant threats to both ecosystems and the natural environment. Conventional methods for treating dye-contaminated water have several limitations, including high costs and complex operational processes. This study investigated a sustainable bio-sorbent composite derived from the Capparis decidua plant and eggshells, and evaluated its effectiveness in removing anionic dyes namely tartrazine (E-102), methyl orange (MO), and their mixed system. The research examines the influence of initial concentration, contact time, pH, adsorbent dosage, and temperature on the adsorption properties of anionic dyes. Optimal removal of tartrazine (E-102), methyl orange (MO), and their mixed system was achieved at a pH of 3. The equilibrium was achieved at 80 min for MO and mixed systems, and 100 min for E-102. The adsorption process showed an exothermic nature, indicating reduced capacity with increasing temperature, consistent with heat release during adsorption. Positive entropy values indicated increased disorder at the solid-liquid interface, attributed to molecular rearrangements and interactions between dye molecules and the adsorbent. Isotherm analysis using Langmuir, Freundlich, Temkin, and Redlich-Peterson models revealed that the Langmuir model best fit the experimental data. The maximum adsorption capacities of 50.97 mg/g, 52.24 mg/g, and 56.23 mg/g were achieved for E-102, MO, and the mixed system under optimized conditions, respectively. The pseudo-second-order kinetic model demonstrated the best fit, indicating that adsorption occurs through physical and chemical interactions such as electrostatic attraction, pore filling, and hydrogen bonding. Hence, the developed bio-sorbent could be a sustainable and cost-effective solution for the treatment of anionic dyes from industrial effluents.

Aggregation, toxicity, and biodegradability study of an ionic liquid-based formulation for effective oil spill remediation.

Chemical dispersants are extensively used for marine oil spill remediation. However, the increased toxicity and low biodegradability of these dispersants restrict their employment in the marine environment. Hence, in this work, we have developed an eco-friendly formulation composed of an ionic liquid,1-butyl-3-methylimidazolium lauroyl sarcosinate [BMIM][Lausar] and sorbitan monooleate (Span) 80. Micellar and interfacial parameters, dispersion effectiveness, as well as the toxicity and biodegradability of the developed formulation were investigated. Micellar properties confirmed a high degree of synergism among the surfactant molecules and the formation of stable micelle. The dispersion effectiveness, at dispersant-to-oil ratio (DOR) of 1:25 (v/v), against three crude oils (Arab, Ratawi, and Doba) was assessed. We achieved a dispersion effectiveness of 68.49%, 74.05%, and 83.43% for Ratawi, Doba, and Arab crude oil, respectively, using a 70:30 (w/w) ratio of Span 80 to [BMIM][Lausar]. Furthermore, the results obtained from optical microscopy and particle size analysis (PSA) indicated that the oil droplet size decreased with higher DOR. Additionally, acute toxicity experiments were conducted on zebrafish (Danio rerio) using the developed formulation, confirming its non-toxic behavior, with LC50 values of 800 mg/L after 96 h. The formulation also exhibited high biodegradability, with only 25.01% of the original quantity remaining after 28 days. Hence, these results suggest that the new formulation has the potential to be a highly effective and environmentally friendly dispersant for oil spill remediation.