ABSTRACT
In this work, ammonia intercalated zinc hydroxide chloride hydrate (ZHC-NH3), Zn5(OH)8Cl2.4[(H2O)x(NH3)1-x)] was synthesised using precursor, [ZnCl2.2{HONC(CH3)2}] by sol-gel method in presence of ammonia and characterised by FT-IR, SEM-EDX, and XRD analysis. On sintering at 500°C, ZHC-NH3 transformed to ZnO nanoparticles (ZnO NPs) as confirmed by the XRD patterns. ZHC-NH3 has nanoplates-like morphology with a positive surface charge (+28.8 mV) while synthesised ZnO nanoparticles (ZnO-NPs) have spherical morphologies with negative surface charge (−8.28 mV). Band gap of 2.7 eV was observed in ZHC-NH3 while in ZnO NPs it was obtained as 3.3 eV. A comparison has been done on the photocatalytic activities of ZHC-NH3 and ZnO NPs towards the degradation of methylene blue (cationic dye) and methyl orange (anionic dye) under sunlight and it was found that photo-degradation of anionic dye, methyl orange is superior (96.28%) in presence of ZHC-NH3 photocatalyst as compared to ZnO photocatalyst (55.42%). The adsorption capacities of ZHC-NH3 towards Pb2+, Cd2+, and Cr3+ heavy metal ions were found 47.00 mg. g−1, 20.40 mg. g−1, and 48.85 mg. g−1 whereas ZnO-NPs have adsorptions capacities of 46.97 mg. g−1, 43.07 mg. g−1, 29.21 mg. g−1, for Pb2+, Cd2+, and Cr3+ heavy metal ions, respectively.
Acknowledgments
We are grateful to Manipal University Jaipur’s central analytical facilities for providing characterisation and analysis facilities (SEM, TGA, FT-IR, AAS, and UV studies), as well as MNIT Jaipur’s Material Research Centre for XRD analysis. We are grateful for the financial support provided by Manipal University Jaipur (seed grant number. EF/2017–18/QE04–02)
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Notes on contributors
Deepti Sharma
Ms. Deepti Sharmais working as Research Scholar at Manipal University Jaipur, Rajasthan, India. She Completed her M.Phil from Maharshi Dayanand Saraswati University Ajmer, Rajasthan, India. Her Research interests are Modification of metal oxide composites, synthesis and Characterization of photocatalytic activities, photo-oxidation and Water Treatment and Recycling.
A.K. Sinha
Prof. A. K. Sinha is a Vice-Chancellor at Chhatrapati Shivaji Maharaj University, Navi Mumbai-410206, Maharashtra, India. His Research areas are Environmental Geology, Hydrogeology and water quality.
Veena Dhayal
Dr. Veena Dhayalis an Associate Professor in the Department of Chemistry at Manipal University Jaipur, Rajasthan, India. She completed her Ph.D. in Inorganic Chemistry from the University of Rajasthan Jaipur, Rajasthan India, in 2009. Her research areas are Metal-organic Chemistry, Coordination Chemistry, Nano-synthesis: Nano-powder and nano-scaled coatings by Sol-Gel, solvothermal, CVD, dip coating, spray pyrolysis deposition, composites, Corrosion protection, Photo-catalysis.