Synthesis of TiO₂/ZnO electrospun nanofibers coated-sewage sludge carbon for adsorption of Ni(II), Cu(II), and COD from aqueous solutions and industrial wastewaters

Sustainable Approaches for Wastewater Treatment: An Analysis of Sludge-Based Materials for Heavy Metal Removal from Wastewater by Adsorption

“…Nekooghadirli et al [109] found that both Ni 2+ and Pb 2+ adsorption into ZnCl 2 -treated sewage sludge best followed the Langmuir isotherm model, with a maximum adsorption capacity of 88.76 mg g −1 for Pb 2+ and 74.06 mg g −1 for Ni 2+ at 25 • C. They also observed that both metals show endothermic adsorption processes based on thermodynamic studies. Khosravi et al [110] coated sewage sludge on TiO 2 /ZnO nanofibers and hydrolyzed it as a practical modification to remove Ni 2+ and Cu 2+ from aqueous solutions, with maximum adsorption capacities of 282.3 mg g −1 and 298.1 mg g −1 for Ni 2+ and Cu 2+ , respectively. Up to five regeneration cycles by 0.1 M HCl and over 90% removal efficiency of both metals were observed, indicating the accelerated regeneration capacity of the adsorbent.…”

“…pH PZC is the pH of the medium at which the adsorbent surface charge is zero [12]. When the pH of the solution is greater than the pH PZC of the adsorbent, the surface of the adsorbent is negatively charged, providing favorable conditions for cation adsorption [67,110]. The surface of the sludge-based adsorbents is negatively charged by the increase in pH [89,109,110].…”

“…When the pH of the solution is greater than the pH PZC of the adsorbent, the surface of the adsorbent is negatively charged, providing favorable conditions for cation adsorption [67,110]. The surface of the sludge-based adsorbents is negatively charged by the increase in pH [89,109,110]. An increase in pH values till optimum pH values of Ni 2+ (pH 5) and Cu 2+ (pH 6) increased the adsorption capacity of sewage sludge carbon-coated ZnO/TiO 2 nanofibers due to an increase in negatively charged ions on the adsorbent surface in a pH range of 2-8 at 25 • C [110].…”

“…The surface of the sludge-based adsorbents is negatively charged by the increase in pH [89,109,110]. An increase in pH values till optimum pH values of Ni 2+ (pH 5) and Cu 2+ (pH 6) increased the adsorption capacity of sewage sludge carbon-coated ZnO/TiO 2 nanofibers due to an increase in negatively charged ions on the adsorbent surface in a pH range of 2-8 at 25 • C [110]. The formation of Cu(OH) 2 and Ni(OH) 2 at higher pH values reduced the adsorption capacity of Cu 2+ and Ni 2+ into sewage sludge carbon-coated ZnO/TiO 2 nanofibers.…”

Fe3O4@BNPs@ZnO–ZnS as a novel, reusable and efficient photocatalyst for dye removal from synthetic and textile wastewaters

“…Lack of fresh water resources on the one hand and uncontrolled discharge of organic pollutants such as paints into the water on the other hand has made wastewater purification one of the main challenges of the last decade [ [1] , [2] , [3] ].…”