Water pollution has invaded seas, rivers, and tap water worldwide. This work employed commercial Mesquite charcoal as a low-cost precursor for fabricating Mesquite carbon nanoparticles (MUCNPs) using a ball-milling process. The scanning electron energy-dispersive microscopy results for MUCNPs revealed a particle size range of 52.4–75.0 nm. The particles were composed mainly of carbon with trace amounts of aluminum, potassium, calcium, titanium, and zinc. The X-ray diffraction peaks at 26.76 and 43.28 2θ° ascribed to the (002) and (100) planes indicated a crystalized graphite phase. Furthermore, the lack of FT-IR vibrations above 3000 cm⁻¹ showed that the MUCNPs were not functionalized. The MUCNPs’ pore diameter, volume, and surface area were 114.5 Ǻ, 0.363 cm³ g⁻¹, and 113.45 m² g⁻¹. The batch technique was utilized to investigate MUCNPs’ effectiveness in removing chlorohexidine gluconate (CHDNG) from water, which took 90 min to achieve equilibrium and had an adsorption capacity of 65.8 mg g⁻¹. The adsorption of CHDNG followed pseudo-second-order kinetics, with the rate-limiting step being diffusion in the liquid film. The Langmuir isotherm dominated the CHDNG adsorption on the MUCNPs with a correlation coefficient of 0.99. The thermodynamic studies revealed that CHDNG adsorption onto the MUCNPs was exothermic and favorable, and its spontaneity increased inversely with CHDNG concentration. The ball-milling-made MUCNPs demonstrated consistent efficiency through regeneration–reuse cycles.

Herein, nanoscale MgAl₂O₄ (MOA), 10%CuO@MgAl₂O₄ (10Cu@MOA), 10%NiO@MgAl₂O₄ (10Ni@MOA), and 10%CoO@MgAl₂O₄ (10Co@MOA) were synthesized employing butylated hydroxytoluene (the food additive BHT) as a capping agent. The SEM images illustrated average sizes of 38.8, 30.0, 40.8, and 32.7 nm for MOA, 10Cu@MOA, 10Ni@MOA, and 10Co@MOA, respectively, and their BET surface area were 84.4, 141.8, 126.7, and 105.3, respectively. Doxycycline DXC removal was studied employing the MOA, 10Cu@MOA, 10Ni@MOA, and 10Co@MOA, which resulted in q_t values of 57.3, 106.1, 97.7, and 73.9 mg g⁻¹, respectively. The pseudo-second order model best described the DXC sorption onto MOA, 10Cu@MOA, 10Ni@MOA, and 10Co@MOA, and both film diffusion models influenced the DXC sorptions onto the sorbents. The DXC sorption onto the 10Cu@MOA fitted the Freundlich model. The thermodynamics implied endothermic-spontaneous DXC sorption onto the10Cu@MOA. The pH study exposed that the DXC removal by 10Cu@MOA was more effective in a mildly acidic medium (pH = 6.0). Furthermore, the 10Cu@MOA effectiveness in treating surface water contaminated by 5.0 and 10.0 mg L⁻¹ DXC was 99.9% and 98.1%, respectively, while it was 94.7% and 92.5% in treating the concentrations above in seawater, respectively. The reusability study showed a 10% reduction in the 10Cu@MOA’s removal efficiency at the fourth cycle, which is encouraging for real-life applications.

One of the major problems facing humanity in all parts of the world is water pollution. Since carbon nanoparticles (CPs) are known for their excellent absorbability, this study explored preparing CPs via a facilitated ball-milling protocol. Four CP products were prepared with the friction enhancer being variated, typically 0-CPs, 2.5-CPs, 5-CPs, and 10-CPs. The four sorbents were characterized using TEM, EDX, XRD, BET, and FTIR methods. The 0-CPs, 2.5-CPs, 5-CPs, and 10-CPs possessed a BET surface area of 113, 139, 105, and 98.5 m² g⁻¹, respectively, and showed a sorption capacity of 55.6, 147.0, 65.8, and 24.6 mg g⁻¹ when tested with chlorohexidine (CH). Therefore, the 2.5-CPs were selected as the best sorbents among the prepared nanomaterials and employed for further sorption investigations. The CH sorption on the 2.5-CPs followed the pseudo-second-order, and the liquid–film diffusion controlled the CH sorption onto the 2.5-CPs. The Langmuir isotherm model was followed, and the Dubinin–Radushkevich energy was 3.0 kJ mole⁻¹, indicating a physisorption process. The thermodynamic outputs suggested that CH sorption by 2.5-CPs was favorable. Furthermore, the 2.5-CPs sorbent was tested for treating water samples contaminated with 20 mg L⁻¹ of ciprofloxacin, dextromethorphan, guaifenesin, metronidazole, ibuprofen, chlorzoxazone, chlorpheniramine malate paracetamol, and hydro-chlorothiazide. The 2.5-CPs showed an average removal efficiency of 94.1% with a removal range of 92.1% to 98.3% and a 2.21 standard deviation value.

A facile method was adopted to fabricate β-C₃N₄, and it was then doped with manganese and tellurium to obtain novel 10%MnTeO₃@β-C₃N₄ (10%MnTe@β) and 20%MnTeO₃@β-C₃N₄ (20%MnTe@β) nanohybrids. The β-C₃N₄, 10%MnTe@β, and 20%MnTe@β showed surface areas of 85.86, 97.40, and 109.54 m² g⁻¹, respectively. Using ciprofloxacin (CIP) as a pollutant example, 10%MnTe@β and 20%MnTe@β attained equilibrium at 60 and 45 min with q_t values of 48.88 and 77.41 mg g⁻¹, respectively, and both performed better at pH = 6.0. The kinetic studies revealed a better agreement with the pseudo-second-order model for CIP sorption on 10%MnTe@β and 20%MnTe@β, indicating that the sorption was controlled by a liquid film mechanism, which suggests a high affinity of CIP toward 10%MnTe@β and 20%MnTe@β. The sorption equilibria outputs indicated better alignment with the Freundlich and Langmuir models for CIP removal by 10%MnTe@β and 20%MnTe@β, respectively. The thermodynamic analysis revealed that CIP removal by 10%MnTe@β and 20%MnTe@β was exothermic, which turned more spontaneous as the temperature decreased. Applying 20%MnTe@β as the best sorbent to groundwater and seawater spiked with CIP resulted in average efficiencies of 94.8% and 91.08%, respectively. The 20%MnTe@β regeneration–reusability average efficiency was 95.14% within four cycles, which might nominate 20%MnTe@β as an efficient and economically viable sorbent for remediating CIP-contaminated water.