Abstract
This study investigated adsorptive and catalytic behaviour of ZnO and ZnO/NiFe2O4 nanocomposites for the removal and degradation of organic pollutants in tannery wastewater. ZnO and ZnO/NiFe2O4 nanomaterials were synthesized via a green method using Zn, Fe and Ni salts precursor and leaves extract of Anacardium occidentale (linn.). Subsequently, the synthesized samples were characterized by different analytical tools. The adsorptive and catalytic performance of the prepared nanomaterial were assessed using reduction in Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD) and Total Organic Carbon (TOC) in tannery wastewater as indicator parameters. High Resolution Scanning Electron Microscope (HRSEM), High Resolution Transmission Electron Microscope (HRTEM), and X-Ray Diffraction (XRD) analysis of ZnO and ZnO/NiFe2O4 confirmed the formation of hexagonal wurtzite nanoparticle and cubic spinel phase with an average crystallite sizes in the range of 13- 28 nm and 30.44 – 42.53 nm respectively. XRD analysis confirmed no change in the polymorph of ZnO upon the addition NiFe2O4. XPS spectrum showed the existence of the elements in the following oxidation state (+2) for Zn, (+1, +2) for Ni and (+2 and +3) for Fe. BET analysis revealed order of the specific surface area of ZnO/NiFe2O4 (44.61 m2/g) > NiFe2O4 (40.39 m2/g) > ZnO (8.91 m2 /g). The adsorptive and photocatalytic results revealed that 3% ZnO/NiFe2O4 exhibits higher efficiency compared to ZnO and NiFe2O4 nanoparticles alone and in the order of 3% ZnO/NiFe2O4 > NiFe2O4 > ZnO. The study revealed that the prepared nanomaterial behaved better as photocatalyst than as nanoadsorbent.
 Keywords: Adsorption, photocatalytic technology; ZnO; ZnO/NiFe2O4, tannery wastewater
Highlights
Industrial tanning transformation process which deal with the conversion of animal hides and skin into leather generates highly turbid, coloured and foul-smelling wastewater (Hayelom et al, 2014)
The tannery wastewater was collected from a tannery factory along Tudun Wada area in Sokoto, Sokoto State, Nigeria, and stored in clean polythene bottles
The appearance of bright spot confirmed that the prepared ZnO nanoparticles preferentially formed along the (100) and (101) direction
Summary
Industrial tanning transformation process which deal with the conversion of animal hides and skin into leather generates highly turbid, coloured and foul-smelling wastewater (Hayelom et al, 2014). Tannery wastewater contains highly recalcitrant chemical pollutants such as chromium-complex collagen, surfactants, sulfides, chlorides and salts. Several conventional methods; coagulation-flocculation, precipitation, oxidation, ion exchange, membrane filtration, ozonation, activated carbon adsorption, biological, and electrodialysis have been utilized to treat tannery wastewater (Asim et al, 2013). These methods have associated shortcomings such as high cost of reagents, generation of toxic sludge, low efficiency, and sometimes, organic pollutants were only transferred from one phase to another and may even become more toxic than the parent compounds (Pawar et al, 2014)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
