ZnO-based nanocomposites for removal of lead (Pb²⁺) from water/wastewater: a review

Abstract

Purpose This paper aims to investigation of processes for Pb2+ elimination from water/wastewater as a significant public health issue in many parts of world. The removal of Pb2+ ions by various nanocomposites has been explained from water/wastewaters. ZnO-based nanocomposites, as eco-friendly nanoparticles with unique physicochemical properties, have received increased attention to remove Pb2+ ions from water/wastewaters. Design/methodology/approach In this review, different ZnO-based nanocomposites were reviewed for their application in the removal of Pb2+ ions from the aqueous solution, typically for wastewater treatment using methodology, such as adsorption. This review focused on the ZnO-based nanocomposites for removing Pb2+ ions from water and wastewaters systems. Findings The ZnO-based nanocomposite was prepared by different methods, such as electrospinning, hydrothermal/alkali hydrothermal, direct precipitation and polymerization. Depending on the preparation method, various types of ZnO-based nanocomposites like ZnO-metal (Cu/ZnO, ZnO/ZnS, ZnO/Fe), ZnO-nonmetal (PVA/ZnO, Talc/ZnO) and ZnO-metal/nonmetal (ZnO/Na-Y zeolite) were obtained with different morphologies. The effects of operational parameters and adsorption mechanisms were discussed in the review. Research limitations/implications The findings may be greatly useful in the application of the ZnO-based nanocomposite in the fields of organic and inorganic pollutants adsorption. Practical implications The present study is novel, because it investigated the morphological and structural properties of the synthesized ZnO-based nanocomposite using different methods and studied the capability of green-synthesized ZnO-based nanocomposite to remove Pb2+ ions as water contaminants. Social implications The current review can be used for the development of environmental pollution control measures. Originality/value This paper reviews the rapidly developing field of nanocomposite technology.

Highly Active Nanocrystalline ZnO and Its Photo-Oxidative Properties towards Acetone Vapor

“…Figure 2 shows the powder diffraction patterns of the intermediate precipitates and ZnO synthesized at 300 • C. According to the obtained data, ZnO-prec(1) was a twophase sample, consisting of the main phase of orthorhombic zinc ammine carbonate ZnNH 3 CO 3 , a space group Pna2 1 (01-077-5096 card, PDF4), and a small amount of ZnO with a wurtzite structure (card 36-1451, PDF2). The refined unit cell parameters of the synthesized ZnNH 3 CO 3 were a = 9.1488 (11), b = 7.6000 (12), and c = 5.4983 (7). The ZnO-prec( 2) sample was single-phase monoclinic hydrozincite Zn 5 (CO 3 ) 2 (OH) 6 , with a space group C2/m (card 19-1458, PDF2), with refined cell parameters a = 13.6127( 19), b = 6.3301 (12), c = 5.3788 (5), and β = 95.06 (2).…”

“…Zinc oxide with a wurtzite structure is a wide-gap ( eV) n -type semiconductor [ 1 ] that also exhibits outstanding photocatalytic properties, owing to which it can compete with TiO 2 . The photocatalytic activity of ZnO has received interest for technologies such as photoactivated gas sensing [ 2 , 3 ], water splitting [ 4 ], photocatalytic synthesis [ 5 , 6 ], and air and water purification [ 7 , 8 , 9 ]. Moreover, defect engineering methods have been widely developed for ZnO that increase its reactivity by introducing additional surface oxygen vacancies during synthesis or physical treatment [ 10 , 11 ].…”