Highly Efficient Removal of Cu(II) Ions from Acidic Aqueous Solution Using ZnO Nanoparticles as Nano-Adsorbents

Abstract

Water pollution by heavy metals has significant effects on aquatic ecosystems. Copper is one of the heavy metals that can cause environmental pollution and toxic effects in natural waters. This encourages the development of better technological alternatives for the removal of this pollutant. This work explores the application of ZnO nanoparticles (ZnO-NPs) for the removal of Cu(II) ions from acidic waters. ZnO NPs were characterized and adsorption experiments were performed under different acidic pHs to evaluate the removal of Cu(II) ions with ZnO NPs. The ZnO NPs were chemically stable under acidic conditions. The adsorption capacity of ZnO NPs for Cu(II) was up to 47.5 and 40.2 mg·g−1 at pH 4.8 and pH 4.0, respectively. The results revealed that qmax (47.5 mg·g−1) and maximum removal efficiency of Cu(II) (98.4%) are achieved at pH = 4.8. In addition, the surface roughness of ZnO NPs decreases approximately 70% after adsorption of Cu(II) at pH 4. The Cu(II) adsorption behavior was more adequately explained by Temkin isotherm model. Additionally, adsorption kinetics were efficiently explained with the pseudo-second-order kinetic model. These results show that ZnO NPs can be an efficient alternative for the removal of Cu(II) from acidic waters and the adsorption process was more efficient under pH = 4.8. This study provides new information about the potential application of ZnO NPs as an effective adsorbent for the remediation and treatment of acidic waters contaminated with Cu(II).

Adsorption mechanism and modeling of radionuclides and heavy metals onto ZnO nanoparticles: a review

“…The peaks at 31.71°, 34.38°, 36.30°, 47.52°, 56.56°, 62.91°, and 67.93° correspond to the (10 0), (0 02), ( 101), ( 102), ( 110), ( 103), and (112) planes of zinc oxide nanoparticles, respectively. The diffractions are consistent with the wurtzite hexagonal structure of zinc oxide nanoparticles (JCPDS 36-1451) Cu(II) adsorption reported (Leiva et al 2021), where a negative adsorption capacity was presented. It is rare to obtain a negative adsorption capacity for an adsorbent as other researchers obtained a positive adsorption capacity (5.084-137.5 mg/g) of ZnONPs for Cu(II) ions (Mahdavi et al 2012;Wang et al 2018;Primo et al 2020;Ali and Hassan 2022).…”

“…However, it is not recommended to conclude on the chemical or physical nature of adsorption based on the good fit of the Langmuir or Freundlich model alone, rather a reliable conclusion would involve a holistic consideration of the isotherm, kinetics thermodynamics, desorption, and mechanistic interpretations. Furthermore, the favorability of the adsorption process or efficient interaction between the metal ions in solution and ZnONPs can be deduced from the Freundlich n value in the range of 1-10 (Chukwuemeka-Okorie et al 3, it is observed that the values of n obtained for heavy metals and radionuclides adsorption were all in the favorable range except for a few studies involving the adsorption of Cu(II), Pb(II) and Pd(II) (Somu and Paul 2018;Primo et al 2020;Leiva et al 2021;Davarnejad and Nikandam 2022). This shows that metal contaminants in water and ZnONPs have a good affinity for efficient water decontamination.…”

Zirconium preconcentration from zircon raffinate using gamma radiation–induced polymerization of reduced graphene oxide composite

“…The surface particles are irregular in size as the hydrogen bonds between grafted AA and TOA lead to roughness in the surface (Li et al 2021 ). The roughness surface guarantees reasonable sorption efficiency (Leiva et al 2021 ). After Zr(IV) loading, Fig.…”

Hybrid PET Track-Etched Membranes Grafted by Well-Defined Poly(2-(dimethylamino)ethyl methacrylate) Brushes and Loaded with Silver Nanoparticles for the Removal of As(III)

“…The pH of adsorption medium is one of the most critical factors for evaluating the removal efficiency of the analyte and the suitability of an adsorption system in real applications [ 83 ]. The pH of zero point (pH PZC ) corresponds to the pH at which the positive and negative charges on the surface of an adsorbent are equal [ 84 ]. pH PZC was calculated from the plot of the initial and final pH values ( Figure 8 a) and determined as 5.3 and 6.7 for PDMAEMA- g -PET and Ag@PDMAEMA- g -PET, respectively.…”