Enhancement of biosorption capability of imidazolium-based ionic liquid-treated Prosopis juliflora for the removal of malachite green from wastewater

Abstract

Due to its toxicity effect, treating toxic pollutants discharged from textile effluent is challenging for living beings. In the present study, the comparative biosorption potential of imidazolium-based ionic liquid-treated Prosopis juliflora (ILPJS) and untreated P. juliflora (PJS) was investigated for the removal of toxic pollutant, malachite green (MG) from aqueous solution. The textural, surface morphology, and functional analysis of ILPJS and PJS were examined using BET (Brunauer-Emmett-Teller) analysis, SEM (Scanning electron microscopy) analysis, and FTIR (Fourier-transform infrared spectroscopy) analysis. Textural property (BET surface area) and surface morphology containing irregular heterogeneous surface for ILPJS were significantly improved than PJS, thereby facilitating significant biosorption of MG. Based on the conventional optimization studies, the essential biosorption parameters for the removal of MG using ILPJS were found to be: initial pH (9.0), contact time (30 min), and biosorbent dosage (0.2 g). The maximum biosorption capacity of PJS and ILPJS were obtained to be 6.91 and 13.64 mg/g at 40 °C, respectively. The spontaneous and endothermic biosorption of MG was confirmed by thermodynamic analysis. The regeneration study indicated the greater reusability of ILPJS and PJS for MG removal till the fifth cycle. Based on the previous literature, this is the first report comparing the removal of toxic pollutant MG using ILPJS and PJS.

NOVELTY STATEMENT

Prosopis juliflora is an invasive weed that causes a severe challenge to ecological diversity and rural livelihoods due to the continuous consumption of water throughout the year, leading to the depletion of groundwater reserves. To control its invasion and growth, weed has been applied as biosorbents to remove toxic pollutant, malachite green (MG). This is the first report comparing the pretreatment of P. juliflora using imidazolium-based ionic liquid (ILPJS) with raw P. juliflora (PJS) for the biosorption of MG. The biosorption capacity of ILPJS for MG removal was 1.97 times higher than PJS. The enhancement in biosorption capacity might be the possibility of better textural and surface morphology of chemically treated P. juliflora. Thermodynamic studies revealed the endothermic and spontaneous nature of the biosorption of MG on PJS. With the invasion of this weed over thousands of hectares of land in India, PJS is the ideal biosorbent for removing toxic chemical pollutants and preserving the groundwater level.

Keywords:

• Biosorption
• ionic liquid
• malachite green
• Prosopis juliflora

Acknowledgments

All authors are thankful to the management of SASTRA Deemed to be University, Thanjavur, Tamil Nadu, India, for providing TRR Research scheme fund, infrastructure, and research facilities to complete this research work. The authors thank Dr K. Abirami, Assistant Prof. SASHE, SASTRA Deemed to be University, Thanjavur, for providing language assistance.

Author contributions

Karthikeyan Asaithambi: writing—original draft, formal analysis, data curation, investigation, and writing—review and editing. Sameeha Syed Abdul Rahman: visualization and investigation. Saroja Pasupathi: visualization and investigation. Chidambaram Sabarathinam: writing—review and editing. Sugumaran Karuppiah: writing—review and editing, data curation, and resources. Mahalakshmi Mathivanan: conceptualization, methodology, writing—review and editing, supervision, and project administration. Rathinakumar Vedhachalam: supervision, investigation, writing—review and editing, project administration, and resources.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.