Search

Environmental Chemistry Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad-211 002, Uttar Pradesh, India E-mail : mcc46@rediffmail.com Fax : 91-53-22541786 The aim of this article is to provide updated, concise yet accurate information about nanotechnology and magnetic nanoparticles in the fields of high societal impact such as environment and biomedicines based on scientific literatures and authoritative reports. The article also includes some visions of potential of applications of nanotechnology, whilst keeping the discussion at the realistic level. This article has been written with the purpose of supporting and enhancing the knowledge of college students, non-governmental organizations, trade unions and industrial workers, as well as other working groups in learning about the nanotechnology and magnetic nanoparticles and its potential in these diverse areas of applications. The authors' intention is to provide those groups forming a balanced view of nanotechnology and magnetic nanoparticles, so to promote a constructive dialogue about this emerging technology. Other aspects of this discussion, such as potential environmental risks of nanoparticles, health and safety aspects, and challenges related to nanotechnology has been also covered in this article. more...

The application of nanomaterials for water treatment has gained impetus in recent years. Nano-adsorbents offer significant decontamination potential due to their unique characteristics. Present study deals with synthesis and application of alumina nanoparticles for removal of an anionic dye, Orange G (OG) from aqueous solutions. The properties of synthesized nanoparticles were investigated by FTIR, TG/DTA, XRD, TEM, SEM, EDX and N2 adsorption-desorption techniques. The effect of various important parameters on dye removal was examined and adsorption was found to be highly pH dependent and maximum removal of 98.4% was observed at pH 2.5. The presence of interfering anions such as SO42−, PO43−, and C2O42− was found to be limiting factor of the adsorption process. The kinetic results demonstrated that the sorption process was described by pseudo-second-order model. Mechanism of adsorption process was also interpreted with the help of diffusion models and the results exhibited that external diffusion governed the overall sorption process. The Langmuir model yielded a good fit for the experimental data with high adsorption capacity (93.3 mg/g at 303 K). The evaluated thermodynamic parameters ΔG°, ΔH° and ΔS°, proposed that adsorption of OG was spontaneous, feasible, and exothermic under investigated conditions. Desorption experiments confirmed that the exhausted adsorbent can be successfully regenerated and can be effectively reused up to four successive cycles with almost the same sorption capacity resulting in reducing cost of treatment. The adsorption performance of alumina nanoparticles was also tested by using real wastewater and results indicated that nano alumina is proficient for the treatment of multi-solute system also. Keywords: Alumina nanoparticles, Isotherm, Kinetics, N2 adsorption-desorption, Regeneration, TGA/DTA more...

In recent years, microbial degradation and bioremediation approaches of polychlorinated biphenyls (PCBs) have been studied extensively considering their toxicity, carcinogenicity and persistency potential in the environment. In this direction, different catabolic enzymes have been identified and reported for biodegradation of different PCB congeners along with optimization of biological processes. A genome analysis of PCB-degrading bacteria has led in an improved understanding of their metabolic potential and adaptation to stressful conditions. However, many stones in this area are left unturned. For example, role and diversity of uncultivable microbes in PCBs degradation is still not fully understood. Improved knowledge and understanding on this front will open up new avenues for improved bioremediation technologies which will bring economic, environmental and societal benefits. This article highlights on recent advances in bioremediation of PCBs in soil. It is demonstrated that bioremediation is the most effective and innovative technology which includes biostimulation, bioaugmentation, phytoremediation, rhizoremediation etc. and acts as a model solution for pollution abatement. More recently, transgenic plants and genetically modified microorganisms have proved to be revolutionary in the bioremediation of PCBs. Additionally, other important and aspects such as pretreatment using chemical/physical agents for enhanced biodegradation are also addressed. Efforts have been made to identify challenges, research gaps and necessary approaches which in future can be harnessed for successful use of bioremediation under field conditions. Emphases have been given on the quality/efficiency of bioremediation technology and its related cost which determines its ultimate acceptability. more...

Environmental Chemistry Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad-211 002, Uttar pradesh, India E-mail : sushbanerjee9@gmail.com Fax : 91-532-2541786 In this work, the performance of a nanocrystalline LSCF composite as a cathode material was investigated. The cathode LSCF composite was successfully synthesized via gel-combustion route. The synthesized LSCF composite material was characterized for microstructural and electrochemical performance by SEM, XRD, BET, FTIR, TGA-DTA, and impedance spectroscopy. The prepared LSCF material shows the high surface area of 68 m2/g. The XRD analysis reveals the nanocrystalline structure of synthesized material. FTIR spectra confirm the formation of mixed metal oxide at high temperature. TGA/DTA analysis reveals that the synthesized LSCF composite is highly stable at high temperatures. The impedance measurement suggested that as-synthesized LSCF composite material can be used as cathode in the fabrication of IT- OFCs. more...

Environmental Chemistry Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad-211 002, Uttar Padesh, India E-mail : ravindragautam1987@gmail.com, mcc46@rediffmail.com Manuscript received online 15 February 2015, accepted 28 April 2015 Superparamagnetic Fe3O4 nanoparticles with diameter of ~7 nm were prepared by a colloidal method, without employing surfactants and using precursors like FeCl3·6H2O, FeSO4·7H2O, deionized water and using NH4OH solution (29% vol.) as precipitating agent. The synthesized product was characterized by X ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy attached with energy dispersive X-ray (SEM-EDS), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett- eller (BET) surface area, thermogravimetric analysis (TGADTG), and atomic force microscopy (AFM). The hysteresis loops of the magnetite nanoparticles were measured using a superconducting quantum interference device (SQUID) and the results showed a superparamagnetic behavior at room temperature. &nbsp more...

Pollution by metal and metalloid ions is one of the most widespread environmental concerns. They are non-biodegradable, and, generally, present high water solubility facilitating their environmental mobilisation interacting with abiotic and biotic components such as adsorption onto natural colloids or even accumulation by living organisms, thus, threatening human health and ecosystems. Therefore, there is a high demand for effective removal treatments of heavy metals, making the application of adsorption materials such as polymer-functionalized nanocomposites (PFNCs), increasingly attractive. PFNCs retain the inherent remarkable surface properties of nanoparticles, while the polymeric support materials provide high stability and processability. These nanoparticle-matrix materials are of great interest for metals and metalloids removal thanks to the functional groups of the polymeric matrixes that provide specific bindings to target pollutants. This review discusses PFNCs synthesis, characterization and performance in adsorption processes as well as the potential environmental risks and perspectives. more...

Environmental Chemistry Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad-211 002, Uttar Pradesh, India E-mail : sushbanerjee9@gmail.com, ravindragautam1987@gmail.com, amita_ecsl@rediffmail.com, mcc46@rediffmail.com Manuscript received 25 January 2014, accepted 05 February 2014 The study of adsorption characteristics of a metal organic framework material (Cu-DTO) for the adsorptive removal of a hazardous dye, Acid Orange 10 (AO-10) from aqueous solutions was undertaken. Cu-DTO complex showed fast adsorption with an equilibrium time of 20 min. Lower concentration range favored the removal. Solution pH also influenced the adsorption process and removal was higher at lower pH. The adsorption isotherm study revealed that Freundlich model fitted the data better indicating a multilayer adsorption on the surface of adsorbent. The adsorption capacity decreased with increasing temperature and maximum adsorption capacity of the Cu-DTO was found to be 3.14 × 10-4 mol/g at 303 K. Kinetic study indicated that process of removal followed pseudo-second order kinetics. The removal of the dye was spontaneous. Desorption studies revealed that the adsorbent could be used without loss of capacity for two cycles. more...

Environmental Chemistry Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad-211 002, Uttar Pradesh, India E-mail: mcc46@rediffmail.com Fax: 91-532-2541786 Department of Chemistry, Bose Institute, 93/1, A chary a Prafulla Chandra Road, Kolkata-700 009, India Manuscript received online 09 October 2012, revised 14 October 2012, accepted 16 October 2012 In the present study, activated carbon had been prepared from \(Oplismenus\) \(frumentaceus\) (Jhangora) husk for the removal of Brilliant Green dye (BG) from aqueous solution. The surface study of \(Oplismenus\) \(frumentaceus\) husk activated carbon (OFHC) was investigated using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Batch studies were performed to optimize various experimental parameters. Optimum conditions were found to be at initial pH =7, contact time = 90 min and adsorbent dose = 4 g/L. The study also reveals that pH changes the structural stability of BG and its color intensity decreased as the pH increased. The equilibrium isotherm data were analyzed using Langmuir, Freundlich and Temkin isotherm model. It was found that Freundlich equilibrium isotherm best fits in the experimental data. The results clearly showed that the multi layer adsorption capacity of OFHC was 20.83 mg/g. The adsorption of BG onto OFHC followed pseudo-second order kinetics. Thermodynamic parameters such as ∆G° , ∆H° and ∆S° were also evaluated and the study reveals that adsorption of BG onto OFHC is favorably influenced by an increase in the temperature of the adsorption process. The experimental studies have indicated that OFHC could be employed as good alternative in wastewater treatment for the removal of BG. more...

Environmental Chemistry Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad-211 002, Uttar Pradesh, India E-mail : mcc46@rediffmail. com, vandani. raw at 1986@gmail. com Manuscript received online 19 April 2012, revised 03 July 2012, accepted 10 July 2012 In the present study, agricultural waste \(Oplismenus\) \(frumentaceus\) husk (OFH) was used as an adsorbent. Batch adsorption studies were performed for the removal of Brilliant Green Dye (BG) from aqueous solution by varying the parameters like solution pH, adsorbent dose and initial BG concentration. The experimental data were analyzed by the Langmuir and Freundlich adsorption isotherm models. The adsorption data were fitted well to Langmuir isotherm model than to Freundlich isotherm. Adsorption rate constants were determined by using pseudo-first order and pseudo-second order rate equations. The results clearly showed that the adsorption of BG onto OFH follows pseudo-second order model. Since \(Oplismenus\) \(frumentaceus\) husk has never been used as adsorbent for the removal of dyes, the result revealed that the \(Oplismenus\) \(frumentaceus\) husk is a cost effective adsorbent for the removal of BG from aqueous solution. more...