Effective removal of malachite green from local dyeing wastewater using zinc-tungstate based materials

Hassana Ladio Abubakar; Jimoh Oladejo Tijani; Ambali Saka Abdulkareem; Titus Chinedu Egbosiuba; Mann Abdullahi; Saheed Mustapha; Emmanuel Ayorinde Ajiboye

doi:10.1016/j.heliyon.2023.e19167

Effective removal of malachite green from local dyeing wastewater using zinc-tungstate based materials

Heliyon. 2023 Aug 16;9(9):e19167. doi: 10.1016/j.heliyon.2023.e19167. eCollection 2023 Sep.

Authors

Hassana Ladio Abubakar¹, Jimoh Oladejo Tijani^{1

2}, Ambali Saka Abdulkareem^{3

2}, Titus Chinedu Egbosiuba^{4

2

5}, Mann Abdullahi¹, Saheed Mustapha^{1

2}, Emmanuel Ayorinde Ajiboye⁶

Affiliations

¹ Department of Chemistry, Federal University of Technology, PMB. 65, Minna, Niger State, Nigeria.
² Nanotechnology Research Group, Africa Centre of Excellence for Mycotoxin and Food Safety, Federal University of Technology, P.M.B 65, Bosso, Minna, Niger State, Nigeria.
³ Department of Chemical Engineering, Federal University of Technology, PMB. 65, Minna, Niger State, Nigeria.
⁴ Department of Chemical Engineering, Chukwuemeka Odumegwu Ojukwu University, P.M.B 02, Uli Campus, Anambra State, Nigeria.
⁵ Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843, USA.
⁶ Department of Chemical Engineering, Hydrometallurgy Unit, University of Cape Town, South Africa.

Abstract

The frequent use of an industrial dye such as malachite green (MG) has caused major water body deterioration and is one of the most pressing global challenges, demanding effective treatment techniques. To solve these issues, a simplistic method was developed to synthesize zinc-tungstate (ZnWO₄) nanoparticles and also dope the surface matrix of the ZnWO₄ nanoparticles using nonmetals of boron (B), carbon (C), and nitrogen (N) at different ratios for enhanced MG removal from wastewater. The prepared nanomaterials were characterized by different methods for crystal structure composition, surface properties, surface morphology, microstructures, functional groups, and elemental oxidation states. The BET analysis revealed a mesoporous structure with surface areas of 30.740 m²/g for ZnWO₄, 38.513 m²/g for ZnWO₄@BCN, 37.368 m²/g for ZnWO₄@BCN/B, 39.325 m²/g for ZnWO₄@BCN/C, and 45.436 m²/g for ZnWO₄@BCN/N nanocomposites. The best removal of MG was accomplished at pH (8), contact period (50 min), nanoadsorbent dose (0.8 g/L), initial MG concentration (20 mg/L), and temperature (303 K). The maximum adsorption capacities of ZnWO₄ and ZnWO₄@BCN/N towards MG were 218.645 and 251.758 mg/g, respectively. At equilibrium, the Freundlich isotherm and pseudo-second-order kinetic models were the best fits for the experimental data of MG adsorption on both nanoadsorbents. After eight cycles of adsorption and desorption, both ZnWO₄ and ZnWO₄@BCN/N were found to be good at removing MG, with efficiencies of 71.00 and 74.20%, respectively. Thermodynamic investigations further validated the spontaneity and endothermic nature of the adsorption process. All study findings confirm the nanoadsorbents exceptional capability and economic feasibility for removing MG dye.

Keywords: Adsorption; Dyeing wastewater; Malachite green; Reusability; Zinc-tungstate oxide.