This paper reports dehalogenation of various organohalides, especially aliphatic halocarbons and pesticides at reduced graphene oxide-silver nanocomposite (RGO@Ag). Several pesticides as well as chlorinated and fluorinated alkyl halides were chosen for this purpose. The composite and the products of degradation were characterized thoroughly by means of various microscopic and spectroscopic techniques. A sequential two-step mechanism involving dehalogenation of the target pollutants by silver nanoparticles followed by adsorption of the degraded compounds onto RGO was revealed. The composite showed unusual adsorption capacity, as high as 1534 mg/g, which facilitated the complete removal of the pollutants. Irrespective of the pollutants tested, a pseudo-second-order rate equation best described the adsorption kinetics. The affinity of the composite manifested chemical differences. The high adsorption capacity and re-usability makes the composite an excellent substrate for purification of water. © 2016 Elsevier B.V.

Soujit Sen Gupta

Pradeep Thalappil

Koushik D

Sen Gupta S

Maliyekkal S.M

Pradeep T.

Adsorption

Degradation

Graphene

Nanocomposites

Pesticides

Pollution

Purification

Water treatment

Adsorption capacities

HIGH ADSORPTION CAPACITY

PSEUDO-SECOND-ORDER RATE EQUATION

PURIFICATION OF WATER

Reduced graphene oxides

SILVER NANOCOMPOSITES

Spectroscopic technique

Water Purification

Silver

Drinking water

Graphene oxide

pesticide

silver nanoparticle

aliphatic hydrocarbon

carbon

nanoparticle

pollutant removal

Reaction kinetics

Adsorption kinetics

article

binding affinity

Biodegradation

chemical reaction kinetics

Chlorination

concentration (parameters)

dehalogenation

Fluorination

waste component removal

water management

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Journal of Hazardous Materials

As(III) and As(V) as well as mixed forms of the same could be effectively scavenged by a composite with fast kinetics allowing the creation of an affordable arsenic-free drinking water solution for point-of-use applications. The granular composites, composed of iron oxyhydroxide-chitosan nanostructures, were synthesized by a green synthetic route, which in general involves the hydrolysis of a metal precursor-chitosan complex using an alkaline medium followed by washing and drying at ambient conditions. Metal ion precursor used for the preparation of the composite was Fe3+. All syntheses were carried out in deionized water, while natural ground water or tap water was used for testing. An iron oxyhydroxide-chitosan nanostructure was synthesized. 25 mg of confined metastable 2-line ferrihydrite (CM2LF) was shaken with 100 mL of natural tap water. Arsenic removal efficiency of CM2LF was measured by spiking the natural tap water with As(III) and As(V) separately. Thereafter, the water was left standing for 1.5 h and subsequently the leftover arsenic concentration in treated water was analyzed using inductively coupled plasma mass spectrometry (ICP-MS) after acidification with 5% HNO3. Experiments with water filtration cartridges are described in the main Text. The unprecedented large capacity in field conditions is attributed to the inherent structure of the composite with confined metastable 2-line ferrihydrite in biopolymer cages, which allows the creation of effective adsorption sites. The arsenic adsorption capacity of the composite is 1.4 to 7.6 times better than the available compositions.

Advanced Materials

Confined Metastable 2-Line Ferrihydrite for Affordable Point-of-Use Arsenic-Free Drinking Water

Unprecedented adsorption of chlorpyrifos (CP), endosulfan (ES), and malathion (ML) onto graphene oxide (GO) and reduced graphene oxide (RGO) from water is reported. The observed adsorption capacities of CP, ES, and ML are as high as ~1200, 1100, and 800 mg g(-1) , respectively. Adsorption is found to be insensitive to pH or background ions. The adsorbent is reusable and can be applied in the field with suitable modifications. A first-principles pseudopotential-based density functional analysis of graphene-water-pesticide interactions showed that the adsorption is mediated through water, while direct interactions between graphene and the pesticides is rather weak or unlikely.

Small

Graphene: A reusable substrate for unprecedented adsorption of pesticides

This paper describes a green method for the synthesis of graphenic material from cane sugar, a common disaccharide. A suitable methodology was introduced to immobilize this material on sand without the need of any binder, resulting in a composite, referred to as graphene sand composite (GSC). Raman spectroscopy confirmed that the material is indeed graphenic in nature, having G and D bands at 1597 and 1338 cm -1, respectively. It effectively removes contaminants from water. Here, we use rhodamine 6G (R6G) as a model dye and chloropyrifos (CP) as a model pesticide to demonstrate this application. The spectroscopic and microscopic analyses coupled with adsorption experiments revealed that physical adsorption plays a dominant role in the adsorption process. Isotherm data in batch experiments show an adsorption capacity of 55 mg/g for R6G and 48 mg/g for CP, which are superior to that of activated carbon. The adsorbent can be easily regenerated using a suitable eluent. This quick and cost-effective technique for the into a commercial water filter with appropriate engineering. © 2012 American Chemical Society.

ACS Applied Materials and Interfaces

Graphene from sugar and its application in water purification

Langmuir

Migration of Silver Nanoparticles from Silver Decorated Graphene Oxide to Other Carbon Nanostructures

ACS Applied Materials & Interfaces

Mussel-Inspired Synthesis of Polydopamine-Functionalized Graphene Hydrogel as Reusable Adsorbents for Water Purification

J. Mater. Chem. A

Graphene-coated silica as a highly efficient sorbent for residual organophosphorus pesticides in water

Rapid dehalogenation of pesticides and organics at the interface of reduced graphene oxide-silver nanocomposite

Journal	Data powered by TypesetJournal of Hazardous Materials
Publisher	Data powered by TypesetElsevier B.V.
ISSN	03043894
Open Access	No