Original Research Paper Green synthesis of nickel oxide nanoparticles and studies of their photocatalytic activity in degradation of polyethylene films A.A. Olajire a,⇑ , A.A. Mohammed b a Industrial/Environmental Unit, Department of Pure and Applied Chemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria b Department of Industrial Chemistry, University of Ilorin, Ilorin, Nigeria article info Article history: Received 8 August 2019 Received in revised form 9 September 2019 Accepted 11 October 2019 Available online xxxx Keywords: Polyethylene film Photocatalytic degradation Nickel oxide nanoparticles Green synthesis Ananas comosus abstract Nickel oxide nanoparticles (NiO NPs) were synthesized using Ananas comosus leaf extract, and were char- acterized by UV–Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, high resolution trans- mission electron microscopy (HRTEM), Energy dispersive X-ray (EDX) and X-ray diffraction (XRD) techniques. The FTIR analysis confirms the formation of the NiO with appearance of NiAO band at 468 cm 1 . The HRTEM analysis reveals that the NiO NPs size was in the range of 0.63–5.75 nm, with an average particle size of 1.42 ± 1.76 nm. The EDX analysis shows clear peaks of Ni (2.7%) and O (5.74%) in the spectrum. The peaks of XRD analysis at (2h) 30°, 43.89°, 60.16°, 77.95° and 82.94° were assigned to (1 1 1), (2 0 0), (2 2 0), (3 1 1) and (2 2 2) planes of the face-centered cubic (fcc) lattice of NiO. The photocatalytic properties of the NiO NPs were studied through the solid phase degradation of low-density polyethylene (LDPE) film. We observed that polymeric nanocomposites (NCs) showed a sig- nificant weight loss of 33 ± 1.6% compared with the pure LDPE (8.6 ± 0.7%) after exposure to solar light irradiation for 240 h, while the nanocomposites under the dark condition gave a weight reduction of 1.90 ± 0.05 at the end of 240 h. The FTIR analysis also confirms the presence of carbonyl group, a degra- dation product of LDPE, with carbonyl index of 0.4. All these important factors showed that NiO is an effective photocatalyst. The study therefore suggests the incorporation of NiO NPs into the polymer matrix so as to enhance its photodegradation. Ó 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved. 1. Introduction Nickel oxide (NiO) has in recent times attracted the attention of scientists worldwide for various technological applications includ- ing antiferromagnetic materials [1], electrode materials for lithium-ion batteries [2], gas sensors adsorbents [3], and electro- chemical super capacitors [4]. Being a wide band gap (3.6– 4.0 eV) p-type semiconductor, it is extensively applied in many fields as adsorbents, solar and fuel cells, photocatalytic agents, gas sensors, magnetic and antibacterial materials [5,6]. Various physical and chemical methods such as anodic arc plasma [7], sol-gel [8], precipitation [9], solvothermal [10], sonochemistry [11], pulse laser ablation [12–14], microwaves [15] and thermal decomposition [16–18] have been used for the synthesis of metal oxide nanoparticles, particularly NiO NPs. However, these conven- tional synthesis approaches are expensive, require greater energy, not eco-friendly and form hazardous by-products. In recent past, there has been an increasing interest in bionanotechnology because the scheme involves the use of non-hazardous and eco- friendly biomaterials like leaves and roots of plants, bacteria, fungi, algae, and vitamins for the synthesis of metal oxide nanoparticles [6,19–24]. Hence in the present work, NiO nanoparticles are pre- pared by a novel, simple, and green route using Ananas comosus leaf extract, which plays the role of reducing and capping agents. Ananas comosus (L.) Merr (Pineapple) is a tropical plant with an edible fruit. The leaf extract of Ananas comosus has been traditionally known to possess many medical uses as validated by ethno-pharmaceutical research [25]. The qualitative phyto- chemical analysis has also revealed the presence of flavonoids, phenols, tannins, carbohydrates, glycosides, and proteins in the leaf extract of A. comosus [26]. To the best of our knowledge, the potentiality of this plant has not been explored for the synthesis NiO NPs till date. The photocatalytic potential of NiO NPs has recently been explored for various applications including dye removal from wastewater [17,18,20,22,27], and chlorophenol degradation [21]. However, their applications in photodegradation of LDPE are scanty. In this study, we have reported green synthesis https://doi.org/10.1016/j.apt.2019.10.012 0921-8831/Ó 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved. ⇑ Corresponding author. E-mail address: aaolajire@lautech.edu.ng (A.A. Olajire). Advanced Powder Technology xxx (xxxx) xxx Contents lists available at ScienceDirect Advanced Powder Technology journal homepage: www.elsevier.com/locate/apt Please cite this article as: A. A. Olajire and A. A. Mohammed, Green synthesis of nickel oxide nanoparticles and studies of their photocatalytic activity in degradation of polyethylene films, Advanced Powder Technology, https://doi.org/10.1016/j.apt.2019.10.012