Water pollution is a major global challenge given the increasing growth in the industry and the human population. The present study aims to investigate the efficiency of TiO₂ and γ-Al₂O₃ nanoadsorbents for removal of copper (Cu(II)) from aqueous solution as influenced by different chemical factors including pH, initial concentration, background electrolyte and, ionic strength. The batch adsorption experiment was performed according to standard experimental methods. Various isotherm models (Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich) were fitted to the equilibrium data. According to geochemical modeling data, adsorption was a predominant mechanism for Cu(II) removal from aqueous solution. Calculated isotherm equations parameters were evidence of the physical adsorption mechanism of Cu(II) onto the surface of the nanoparticles. The Freundlich adsorption isotherm model could well fit the experimental equilibrium data at different pH values. The maximum monolayer adsorption capacity of TiO₂ and γ-Al₂O₃ nanosorbents were found to 9288 and 3607 mg kg⁻¹ at the highest pH value (pH 8) and the highest initial Cu(II) concentration (80 mg L⁻¹) respectively. Copper )Cu(II) (removal efficiency with TiO₂ and γ-Al₂O₃ nanoparticles increased by increasing pH. Copper )Cu(II) (adsorption deceased by increasing ionic strength. The maximum Cu(II) adsorption (4510 mg kg⁻¹) with TiO₂ nanoparticles was found at 0.01 M ionic strength in the presence of NaCl. Thermodynamic calculations show the adsorption of Cu(II) ions onto the nanoparticles was spontaneous in nature. Titanium oxide (TiO₂) nanosorbents could, therefore, serve as an efficient and low-cost nanomaterial for the remediation of Cu(II) ions polluted aqueous solutions.

To investigate the influence of grape-pruning-residue (GPR) biochar on cadmium (Cd), lead (Pb), copper (Cu) and zinc (Zn) immobilization in a contaminated soil, a laboratory study was conducted with different rates of GPR biochar (0, 2, 5 and 10% w/w) at 25°C. After 1, 2, 4, and 8 weeks of incubation, the Tessier sequential extraction procedure was performed and metal mobility factor (MF) and metal stability index (I_R) were calculated. The exchangeable (EX) and carbonate (CAR) fractions of the metals decreased significantly (p ≤ 0.05) with the biochar addition. The EX metal fractions decreased by 23 to 72%, and the CAR fractions decreased by 51 to 67% in the 10% biochar treatment after 8-week incubation. The MF values of Cd, Pb, Cu and Zn decreased by 47, 62, 70 and 49%, respectively, with addition %10 of the biochar. Biochar addition favored the metal redistribution into more stable fractions and resulted in an increase in I_R values. The results demonstrated that the GPR biochar, especially at high application rate (10%), can effectively immobilize the heavy metals, thereby reducing their mobility in contaminated soils.

The entry of antibiotics, as pollutants, into the environment has created great concerns. Environmental dynamics of antibiotics based on soil chemical properties need to be a better understanding of their chemical behavior. This research is focused on studying the adsorption behavior and kinetic mechanisms of ciprofloxacin (CIP) in an agricultural soil. For this purpose, a batch experiment was conducted at different times (5 min–24 h), and using initial concentrations of CIP (0–1 mmol L⁻¹) in the soil. The adsorption processes as affected by pH and ionic strength were assessed based on the modeling with response surface methodology (RSM). According to the results, the sorption equilibrium was found within 240 min, and the pseudo second-order model was the best for describing the data. Increasing the initial CIP concentration increased CIP adsorption, but increases in ionic strength and pH had an inverse effect. Based on RSM modeling, the CIP adsorption was 7.31 and 7.03 (mg g⁻¹) in the presence of NaCl and CaCl₂ electrolytes, respectively, in the optimized conditions (pH 6.5 and ionic strength 0.01 mol L⁻¹). The spontaneous nature of CIP adsorption was determined based on thermodynamic calculations (ΔG° = −10.8 to −12.4 kJ mol⁻¹). The interaction of pH and ionic strength was described with the quadratic model. The obtained results contribute to understanding the CIP fate in the soil environment and facilitate decisions regarding entry and controlling soil contamination due to this antibiotic.