Remediation of Chlorides from Water Using Prosopis Juliflora Biochars

Abstract Chloride (Cl − ) is one of the pollutants that can cause significant health risks when its concentration is high in water. Utilizing adsorption has a superiority in removing pollutants from water due to its large active surface area, small volume, and high adsorption capacity. Biochar can be used in multifunctional applications, including improvement of soil health, mitigation of greenhouse gas emissions, and remediation of contaminated water sources, among others. Herein, slow pyrolysis was used to create biochar, a small grain, permeable carbonaceous solid from Prosopis juliflora biomass waste residues. The Prosopis juliflora biochar was used to remove Cl − ions in water. The characteristics of the biochar included a weak acidic pH value and an abundance of surface functional groups. The adsorption capacity of the biochar was then determined through its effectiveness in removing Cl − ions in water. The FTIR spectra showed O-H stretching at 2,923.17 cm − 1 , a second peak at 2,923.17 cm − 1 relating to CO 2 absorption, a peak at 1,631.81 cm − 1 ascribed to carboxylate (COO − 1 ), and a peak at 1,053.15 cm − 1 denoting C-O stretching vibration. The Scanning Electron Microscopy characterization indicated that acid treated Prosopis juliflora seeds enhances the active sites for desalination while Energy Dispersive X-ray Spectroscopy analysis of the prepared samples shows mesoporosity on both treated and untreated Prosopis juliflora seeds. The Brunner- Emmett- Teller results show a type IV isotherm with a relative pressure (P/Po > 0.8) in the two samples. The removal capacity of the biochar was then determined through its effectiveness in removing chloride and sodium ions from synthetic water and natural water samples obtained from a borehole in Kalokol. pH 6 gave the best removal capacity after surface modification of the adsorbent. The chloride ion removal efficiency increased with the increased dosage. The adsorption had the best fit in the Langmuir isotherm with an R 2 value of 0.0299 compared to 0.0008 for the Freundlich isotherm. In conclusion, Prosopis juliflora biochar is a promising adsorbent for advancing removal of chlorides from saline water to address water quality challenges as well as promote management of the invasive Prosopis juliflora species.