The discharge of inorganic pollutants like phosphate and fluoride is a cause of mounting concern to the world due to the substantial environmental and human health risk. Adsorption is one of the most common and affordable technologies widely utilized for removing inorganic pollutants such as phosphate and fluoride anions. Investigating efficient sorbents for the adsorption of these pollutants is extremely important and challenging. This work aimed at studying the adsorption efficiency of the Ce(III)-BDC metal-organic framework (MOF) for the removal of these anions from an aqueous solution using a batch mode. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), and scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) techniques evidenced the successful synthesis of Ce(III)-BDC MOF in water as a solvent without any energy input within a short reaction time. The outstanding removal efficiency of phosphate and fluoride was exhibited at an optimized pH (3, 4), adsorbent dose (0.20, 0.35 g), contact time (3, 6 h), agitation speed (120, 100 rpm), and concentration (10, 15 ppm) for each ion, respectively. The experiment on the effect of coexisting ions demonstrated that SO₄^2- and PO₄^3- ions are the primary interfering ions in phosphate and fluoride adsorption, respectively, while the HCO₃^- and Cl^- ions were found to have interfered less. Furthermore, the isotherm experiment showed that the equilibrium data fitted well with the Langmuir isotherm model and the kinetic data correlated well with the pseudo-second-order model for both ions. The results of thermodynamic parameters such as ΔH°, ΔG°, and ΔS° evidenced an endothermic and spontaneous process. The regeneration of the adsorbent made using water and NaOH solution showed the easy regeneration of the sorbent Ce(III)-BDC MOF, which can be reused four times, revealing its potential application for the removal of these anions from aqueous environment.

In the present study, removal of Cr(VI) from aqueous solutions was investigated utilizing Teff straw, the agricultural solid waste product of Tef [Eragrostis tef (Zucc.) Trotter]. The characteristic surface chemistry of the Teff straw was analyzed by FT-IR analysis and the adsorption efficiency of this novel adsorbent was studied using the batch adsorption technique. Different experimental parameters including pH, contact time, adsorbent dose, initial metal ion concentration, and agitation speed were optimized. Equilibrium and kinetic models for Cr(VI) sorption were studied by considering the effects of concentration and contact time at the optimum pH (pH = 2) and agitation speed of 150 rpm. Results of the sorption equilibria were found to fit better to the Langmuir isotherm (R²= 0.9739) than the Freundlich isotherm (R²= 0.9187) and maximum Cr(VI) loading capacity of 3.51 mg/g was determined. On the other hand, kinetics of Cr(VI) sorption on the Teff straw was well defined by the pseudo-second order model (R²= 0.9999). The results obtained showed that the use of Teff straw can be considered as one of the most promising, natural, easily accessible, and low-cost adsorbent for efficient and quantitative removal of Cr(VI) from contaminated wastewaters released from leather industries.

Salting˗out-assisted liquid–liquid extraction coupled with high-performance liquid chromatography was developed for selective extraction and preconcentration of five s-triazine herbicides and three major metabolites of atrazine simultaneously. Under the optimum conditions, detection and quantification limits (ng mL⁻¹) were found in the range 0.02–0.19 and 0.06–0.65, respectively. Linearity ranges (ng mL⁻¹) of 1–60 (ametrin), 2–160 (desethylatrazine, desisopropyl atrazine, secbumetone and terbutryn) and 4–240 (hydroxyatrazine and aziprotryn) were obtained. The relative standard deviations for the intra- and inter-day precisions were in the ranges 0.3–8.5% and 5.4–9.8%, respectively. Relative recoveries of three spiked water samples were in the ranges of 72.5–114.6, 74.6–109.2 and 62.5–109.6% for the river, lake and underground water samples, respectively.