Possible use of waste from marcasite jewelry industry as iron pyrite source incorporated with titanium dioxide for photodegradation of lignin under a halogen tungsten lamp Nithiwach Nawaukkaratharnant a , Pornapa Sujaridworakun b,c , Charusporn Mongkolkachit d , Thanakorn Wasanapiarnpong b,c,⇑ a Metallurgy and Materials Science Research Institute, Chulalongkorn University, Bangkok 10330, Thailand b Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand c Center of Excellence on Petrochemical and Materials Technology, Bangkok 10330, Thailand d National Metal and Materials Technology Center (MTEC), Klong Luang, Pathumthani 12120, Thailand article info Article history: Received 10 March 2020 Received in revised form 2 April 2020 Accepted 3 April 2020 Available online 4 April 2020 Keywords: Pyrite FeS 2 /TiO 2 photocatalyst Semiconductors Marcasite waste Microstructure Lignin degradation Wastewater treatment abstract This paper observes the possibility of utilization of the marcasite waste (MW) from jewelry industry as pyrite FeS 2 source for preparing the pyrite FeS 2 /titanium dioxide (TiO 2 ) photocatalyst composite powder with simple method. The photocatalyst composite powder was fabricated by mixing the washed and milled MW with commercial TiO 2 in ethanol and calcining at 300 °C for 4 h under low oxygen atmo- sphere. The particle was core–shell structure constructed of TiO 2 shell and pyrite FeS 2 core. Photocatalytic activity of the prepared powder, investigated by lignin degradation under irradiation by a halogen tungsten lamp, was higher than that of the commercial TiO 2 . This work provides an opportunity of waste recycling for removing organic matter from wastewater. Ó 2020 Elsevier B.V. All rights reserved. 1. Introduction The industrial waste, can provide an impact on environment, has been a major concern for many years. The waste from marca- site jewelry production process, marcasite waste (MW), composed mainly of pyrite and small amount of other materials. Pyrite FeS 2 is a semiconductor material which is utilized in many applications including photocatalyst because of its surface chemical properties, high absorption coefficient of light and appropriated bandgap (0.95 eV) [1–3]. The photocatalytic activity of pyrite synthesized from pure chemical reagents was studied in many reports. Liu et al. [4] synthesized the pyrite FeS 2 for organic dyes removal by adsorption under dark condition and photocatalysis under ultravi- olet (UV) irradiation. Moreover, the incorporation of pyrite FeS 2 with TiO 2 also studied [5,6]. Lee and Kang [7] prepared the core/shell structured pyrite FeS 2 /anatase TiO 2 composites, which showed high rate of hydrogen production from aqueous methanol under UV irradiation. Although, the photocatalytic activity of syn- thetic pyrite FeS 2 has been studied, pyrite FeS 2 from waste has never been studied before. Furthermore, the photodegradation of lignin, the organic compound in wastewater from agricultural industries [8], using pyrite FeS 2 has never been explored. In this work, the photocatalyst composed of TiO 2 and pyrite FeS 2 from marcasite jewelry production waste was prepared by simple method and the photocatalytic activity of lignin degradation under light source as tungsten halogen lamp was considered. 2. Experimental procedure MW was taken from marcasite jewelry industry in Thailand. As- received MW was washed with acetone several times to remove the organic substances, followed by ball-milling in ethanol for 24 h. Then the suspension was filtrated and dried at 110 °C for 24 h. To prepare composite powder, 4 g of TiO 2 (Degussa, P-25) and 1 g of milled MW was dispersed separately in 50 mL of ethanol and stirred for 1 h. The TiO 2 suspension was dropped into MW suspension and stirred continuously for 1 h. The mixture was then filtrated and dried before firing at 300 °C for 4 h in covered container under https://doi.org/10.1016/j.matlet.2020.127778 0167-577X/Ó 2020 Elsevier B.V. All rights reserved. ⇑ Corresponding author at: Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand. E-mail addresses: Nithiwach.N@chula.ac.th (N. Nawaukkaratharnant), Pornapa. S@Chula.ac.th (P. Sujaridworakun), charuspm@mtec.or.th (C. Mongkolkachit), thanakorn.w@chula.ac.th (T. Wasanapiarnpong). Materials Letters 271 (2020) 127778 Contents lists available at ScienceDirect Materials Letters journal homepage: www.elsevier.com/locate/mlblue