Formulation of Synthesized Zinc Oxide Nanopowder into Hybrid Beads for Dye Separation

Hindawi Publishing Corporation Journal of Nanomaterials Volume 2014, Article ID 967492, 14 pages http://dx.doi.org/10.1155/2014/967492 Research Article Formulation of Synthesized Zinc Oxide Nanopowder into Hybrid Beads for Dye Separation H. Shokry Hassan,1 M. F. Elkady,2,3 A. H. El-Shazly,2 and Hisham S. Bamufleh4 1 Electronic Materials Researches Department, Advanced Technology and New Materials Researches Institute, City of Scientific Researches and Technological Applications, New Borg El-Arab City, Alexandria 21934, Egypt 2 Chemical and Petrochemical Engineering Department, Egypt-Japan University of Science and Technology, New Borg El-Arab City, Alexandria 21934, Egypt 3 Fabrication Technology Department, Advanced Technology and New Materials Research Institute (ATNMRI), City of Scientific Research and Technology Applications, Alexandria 21934, Egypt 4 Department of Chemical & Materials Engineering, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia Correspondence should be addressed to M. F. Elkady; Received 11 December 2013; Revised 11 February 2014; Accepted 28 February 2014; Published 9 April 2014 Academic Editor: Shao-Wen Cao Copyright © 2014 H. Shokry Hassan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The sol-gel prepared zinc oxide nanopowder was immobilized onto alginate-polyvinyl alcohol polymer blend to fabricate novel biocomposite beads. Various physicochemical characterization techniques have been utilized to identify the crystalline, morphological, and chemical structures of both the fabricated zinc oxide hybrid beads and their corresponding zinc oxide nanopowder. The thermal stability investigations demonstrate that ZnO nanopowder stability dramatically decreased with its immobilization into the polymeric alginate and PVA matrix. The formulated beads had very strong mechanical strength and they are difficult to be broken up to 1500 rpm. Moreover, these hybrid beads are chemically stable at the acidic media (pH < 7) especially within the pH range of 2–7. Finally, the applicability of the formulated ZnO hybrid beads for C.I. basic blue 41 (BB41) decolorization from aqueous solution was examined. 1. Introduction The huge increment in pollution level urges scientific community to research with more and more dedication in environmental remediation. One of the important classes of the pollutants is dyes; dyes have been extensively used in industries, such as textile, paper, printing, cosmetics, plastics, and rubber, for the coloration of products [1, 2]. They usually have a synthetic origin and are based on complex aromatic structures which make them stable and difficult to be biodegraded [1]. A small quantity of dyes can color large water bodies, which not only affects aesthetic merit but also reduces light penetration and photosynthesis. Moreover, many dyes are toxic in nature with suspected carcinogenic and mutagenic effects that affect aquatic biota and also human beings [3, 4]. Therefore, the decolorization of dye-containing effluents is considered compulsory prior to discharge by the environmental regulations in most of the countries [5, 6]. In this respect, C.I. basic blue 41 (BB41) is a mono-azo-basic dye of bright blue hue; it is particularly suitable for dyeing acrylic substrates and can also be applied to some polyamide and polyester types, viscose, cotton, and wool. It is also effective as strainer for the identification of avian leukocytes and blood and bone-marrow cells [7]. This basic dye may be considered as one of the most toxic substances. It can cause eye burns which may be responsible for permanent injury to the eyes of human and animals. On inhalation, it can give rise to short periods of rapid or difficult breathing while ingestion through 2 the mouth produces a burning sensation and may cause nausea, vomiting, profuse sweating, mental confusion, and methemoglobinemia [8, 9]. Consequently, BB41 is selected as one of the simulated dye pollutants to assess its sorption behavior to be eliminated from polluted wastewaters. Different techniques have been reported by various investigations for the removal of dyes from water and wastewater, including biological processes, combined chemical and biochemical processes, chemical oxidation, adsorption, coagulation, and membrane treatments; each of these has specific advantages and disadvantages. Among these several conventional chemical and physical methods, the adsorption process is one of the effective techniques that have been successfully employed for dye removal from wastewater. Adsorption is a classical technique which involves a variety of highly porous adsorbents to ensure adequate surface area for adsorption [10]. Accordingly, many porous adsorbent materials have been tested on the possibility for dye removal such as activated carbon [11], peat, chitin, and silica [12]. However, intraparticle diffusion associated with porous adsorbents may reduce the adsorption rate and capacity [13]. Consequently, there is a need to develop alternative novel adsorbents with both large surface area and small diffusion resistance characteristics. Recent advances in the field of nanotechnology offer a class of promising adsorbents that are ultrafine and characterized by their large surface area. Nanosized metal oxide nanoparticles have received considerable attention due to the simple procedure involved in synthesis with low capital cost compared to commercially available activated carbon. Diverse inorganic metal oxides may serve as good adsorbents, due to their relatively high surface area and thermal and chemical stabilities. Among these metal oxide nanopowders, Zinc oxide was distinguished by its significant sorption properties toward the polluted harmful ions presence in wastewater [14]. A wide number of methods have been used to prepare ZnO nanopowders, including homogeneous precipitation in aqueous solution of Zn2+ cations, hydrothermal synthesis, microwave synthesis, solution combustion, pulsed laser deposition, emulsion precipitation, ultrasonic atomization, spray pyrolysis, freeze-drying, and sol-gel processes [15–17]. Regarding the various stated preparation techniques, sol-gel represents one of the fastest growing fields of contemporary chemistry. Accordingly, this preparation technique was utilized for synthesis of ZnO nanoparticles. This is due to the fact that this preparation technique offers several advantages such as being easy, fast, and able to deform materials into complex geometries in a gel state with high purity [18]. Consequently, zinc oxide nanoparticles can be easily prepared using sol-gel technique. In spite of the prepared zinc oxide nanopowder having good adsorbent for dyes, however it is difficult to be handled in the adsorption techniques due to its sma (...truncated)