دانلود رایگان ترجمه مقاله سنتز سبز نانوذرات a-Fe2O3 برای تصفیه آرسنیک (نشریه الزویر 2016)

سنتز سبز نانوذرات a-Fe2O3 برای تصفیه آرسنیک (V) با جنبه تازه ای برای تصفیه لجن

Green synthesis of a-Fe2O3 nanoparticles for arsenic(V) remediation with a novel aspect for sludge management

Abstract

A simple, single step and eco-friendly approach was taken for synthesizing iron oxide nanoparticles using Aloe vera leaf extract. The nanoparticles were characterized by various techniques and used for arsenic(V) remediation in synthetic system with an initial concentration range of 2–30 mg/L. The effect of pH, particle dosage and initial arsenic concentration on arsenic adsorption was investigated using response surface methodology involving five levels Central Composite Design (CCD) considering adsorption capacity as the response. The nanoparticles showed a high sorption capacity of 38.48 mg/g in the experimental range of concentration compared to other inorganic oxide based adsorbents.

A novel approach was adopted for utilization of arsenic contained sludge. As(V) sorbed nanoparticles were used in the preparation of colored soda lime silicate glass. The basic properties such as density, thermal and optical properties were measured for the experimental glass sample and compared with samples containing commercial Fe2O3.

The overall study indicates that the green synthesized iron oxide nanoparticle is a prospective candidate for arsenic remediation in contaminated water. The arsenic contained sludge may be used in preparation of coloured glasses which have wide application in making container bottles and building glasses.

1 Introduction

Nanotechnology has introduced a new dimension in the field of environmental remediation of various toxic contaminants like heavy metals, dyes and pesticides etc. Controlling the particle size and shape at nanoscale results into a large surface area to volume ratio which imparts greater reactivity. Apart from the smaller particle sizes, presence of a large numbers of active sites and the catalytic potential of nanoparticles enable them as potential candidates for wide range of contaminants [1]. Nanoscale iron particles have shown efficiency for detoxification of chlorinated organic solvents, organochlorine pesticides and PCBs [2]. Zhang et al. prepared ferromagnetic carbon coated Fe nanoparticle which could remove over 95% of chromium (VI) in wastewater [3]. Manganese based nanoparticle synthesized using micro-emulsion process and coated with gold was observed as efficient nanosorbents for removal of heavy metals from wastewater [4]. Copper (II) oxide nanoparticles synthesized by thermal refluxing process were found as a potential nano-adsorbent for arsenic removal [5].

Iron oxide based components have a natural affinity for arsenic sorption [6]. Removal of As(V) using magnetic Fe3O4 from municipal waste water has been reported [7]. Fe(III) crosslinked alginate nanoparticles were used in fixed bed column for arsenic (V) removal [8]. Apart from being an effective adsorbent of As(V), the nano-sorbent demonstrated antimicrobial property also. The adsorption–desorption behaviour for As(V) was studied using hydrated iron oxide particles in combination with a macroporous ion-exchange resin at neutral pH [9]. A novel composite material was developed with high arsenic adsorption capacity by encapsulating g-Fe2O3 nanoparticles in macroporous silica [10].

Most of the research studies focus on synthesis of iron oxide nanoparticles by chemical route using reducing agents [11]. Chemical reagents are often toxic, flammable and expensive in nature. In the process of synthesizing magnetite nanoparticles using toxic solvents, hazardous byproducts may generate and the process involves high energy consumption [12]. Therefore, biogenic or green synthesis of nanoparticles has emerged as an environment friendly and promising approach. Application of various plant extracts has been reported for biosynthesis of gold and silver nanoparticles using rapid and nontoxic process [13]. Presence of different phytochemicals, viz. glutathiones, polyphenols, alkaloids as well as various types of proteins, enzymes, polysaccharides and alcoholic compounds in plant extracts facilitate reduction of metal ions and formation of stable nanoparticles [12]. Extracts of Aloe vera leaves were used for production of silver nanoparticles and its antimicrobial activity has been studied [14]. The gel of A. vera leaf acts as a bio-reducing agent for preparation of metal oxide and metal nanoparticle, semiconductors, etc. [15]. Nanocrystalline zinc-aluminate had been synthesized using A. vera leaf extract [15]. Biosynthesis of iron oxide nanoparticles with less than 5 nm were achieved in preferential cubic arrays deriving into magnetite and wuestite-like clusters using alfalfa [16].