Preparation of ZnWO4 (Sanmartinite) Powder Through Mechanochemical Method for Visible Light-Induced Photocatalysis
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RESEARCH ARTICLE-CHEMISTRY
Preparation of ZnWO4 (Sanmartinite) Powder Through Mechanochemical Method for Visible Light-Induced Photocatalysis I. Altinsoy2 · N. Guy1,3 · M. Ozacar1,3 · C. Bindal1,2 Received: 1 August 2019 / Accepted: 13 August 2020 © King Fahd University of Petroleum & Minerals 2020
Abstract ZnWO4 (sanmartinite) powders were produced by mechanochemical synthesis using ZnO and WO3 at 700 rpm for 25, 50 and 100 min, respectively. SEM indicated the ratio of sub-micron-sized ZnWO4 particles was raised, and particle size distribution was homogenized by increasing process time. XRD results revealed the formation of sanmartinite after 100 min milling with 700 rpm. Raman Spectroscopy confirmed the XRD results except detection of WO3 and ZnO traces. The surface area of the samples was ranged between 3.65 and 4.05 m2 /g. Optical band-gap energies of the samples increased from 2.68 to 2.86 eV with further process time. Under the visible light, the highest photocatalytic efficiency for degradation of malachite green dyes was observed in sample ball milled at 700 rpm for 25 min. Samples ball milled at 700 rpm for 100 min have lower photocatalytic activity compared to samples ball milled at 700 rpm 25 and 50 min. The efficiency of photocatalytic activities changed from 45 to 83% after 120-min photocatalysis process. It is possible to claim that ZnWO4 powders are promising photocatalyst. Keywords ZnWO4 · Mechanochemical synthesis · Particle surface area (BET) · Optical band gap · Photocatalytic efficiency
1 Introduction Industries like textile, pulp and paper, food leather, printing, etc. consume lot of fresh water and dispose of contaminated water into soil. In this process, every year about 800,000 tons of synthetic dyes (non-biodegradable, mutagenic and carcinogenic) is dumped into natural water resources causing severe damage to aquatic flora–fauna by depleting the dissolved oxygen in water [1]. Treatment of such organic pollutants through photocatalysis is a cutting-edge technology by virtue of its facile green approach, efficient nature and nontoxic byproducts (H2 O, CO2 and mineral acids) [2]. For
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C. Bindal [email protected] I. Altinsoy [email protected]
1
Biomedical, Magnetic and Semiconductor Materials Research Center (BIMAS-RC), Sakarya University, 54187 Serdivan, Sakarya, Turkey
2
Department of Metallurgy and Materials Engineering, Engineering Faculty, Sakarya University, 54187 Serdivan, Sakarya, Turkey
3
Department of Chemistry, Art-Science Faculty, Sakarya University, 54187 Serdivan, Sakarya, Turkey
efficient photocatalysis, photocatalyst should be cheap, stable, nontoxic and also have high photocatalytic efficiency [3]. The absorption of sufficiently energetic UV light by a wide band-gap semiconductor results in the creation of electrons and holes through a process of electronic excitation between the valence and conductions bands [4, 5]. Once created, these photogenerated charge carriers are able to migrate to the surface of the semiconductor and undergo redox reactions with
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