Solid phase extraction of europium and uranium using Tulsion CH-90 resin

A procedure for the pre-concentration and separation of trace amounts of Eu and U by solid phase extraction using Tulsion CH-90 resin (with imino diacetate functional group) has been developed. The determinations of europium and uranium have been carried out by a radiotracer technique using ^152,154Eu and ²³³U radionuclides. The experiments were carried out using both batch and column techniques. Parameters such as equilibration rate, effect of pH, sorption and desorption of metal ions have been studied. The maximum sorption capacities for Eu and U were found to be 0.31 mmolg^–1 at pH 5.3 and 0.96 mmolg^–1 at pH 3.1 respectively.     

Interfacial mechanisms controlling phase formation in sol-gel derived lead zirconate titanate thin films

An RBS study has been carried out to study the relative extent of Pb diffusion in the substrate from PZT films. It is found that extensive diffusion of Pb occurs into the quartz substrate making the film severely deficient in Pb. No such diffusion occurs in the case of PZT films on sapphire and the concentration of Pb is near stoichiometric, except for a small loss due to volatilization. Excessive Pb deficiency, rather than any epitaxial effect, has earlier been proposed by us to be the crucial factor responsible for the existence of the pyrochlore phase in PZT thin films on substrates such as Si, glass, quartz etc. The present results confirm this. The effects of other process variables such as thickness and chemical composition (Zr/Ti ratio) of the film can also be understood in terms of the same phenomenon.     

The effect of citrate, oxalate, acetate, silicate and phosphate on stability of synthetic arsenic-loaded ferrihydrite and Al-ferrihydrite

The effect of the organic species oxalate, citrate and acetate and the inorganic species silicate and phosphate on release of As(V) from synthetic arsenic-loaded ferrihydrite and Al-ferrihydrite in the pH range 4-8 was investigated. For ferrihydrite, the organic species increased %As(V) extraction in the order: acetatePO4(3-). Competitive adsorption of the investigated organic and inorganic species on ferrihydrite and Al-ferrihydrite could explain the enhanced release of As(V) into solution. However, disproportionate adsorption of other species relative to amount of As(V) release occurs, suggesting that mechanisms other than competitive adsorption are also operative. The results could best be explained in terms of combination of competitive adsorption and processes involving pH-dependent dissolution of ferrihydrite/Al-ferrihydrite, formation of various complex ionic species involving Al(III), Fe(III), As(V), SiO3(2-), PO4(3-), OH-, H+ and organic species: acetate, oxalate and citrate.     

Advancement in treatment of wastewater: Fate of emerging contaminants

The scarcity of industrial and domestic use water has become an important issue as industrial operations and localized pollution have burgeoned over the last decade. Wastewater (WW) treatment for recycling and reuse is gaining importance as an alternate source of water supply to circumvent water shortages. Wastewater treatment requires thorough planning, design, construction, and management of treatment facilities in order to discharge the treated water to the aquatic environment or for recycling and reuse. One detrimental effect of growing populations and urbanization has been the release of many persistent emerging contaminants (ECs) to the environment, mainly detected in WW. The entry of these ECs to the aquatic environment through wastewater treatment plants (WWTPs) may cause different ecological risks such as reproductive toxicity, endocrine disruption, and microbial resistance. The quantification of ECs (in ng or pg level) in complex matrices, such as WW samples recognized through non‐target screening approaches, has played a key role in the planning and design of water treatment facilities. The purpose of this review is to provide information about advancements in wastewater treatment technologies such as constructed wetland (CW) and advanced oxidation processes (AOPs) and the fate of emerging contaminants during these treatments. Further, this review also reports the ecological effects of these contaminants and their by‐products formed during various advanced WW treatment processes. The review also discusses advancements in different analytical techniques for the analysis of ECs in WW.     

Electrochemical behavior of nanostructured graphene nickel phosphorus composite coating on copper

Journal of Applied Electrochemistry - The present work is focused on the effects of graphene addition on the electrochemical performance of environmentally benign nanostructured...     

Post-harvest Processing of Banana: Opportunities and Challenges

Banana has a special place in the daily diet of millions of people around the world for sustenance and nutrient enrichment. Some of the popular food uses of banana are chips, raw ripened fruit, cooked green banana, fermented and unfermented beverages, juice, puree, dried flour for bakery and infant formula food. Banana is also used as a starch source for various chemicals and packaging materials. The storability and functional properties of these products can be altered by the application of various innovative food processing technologies. This review article focuses on different banana products, their potential for non-conventional uses and associated prospective novel processing techniques for value addition and preservation.     

Evaluation of a commercial electronic nose system coupled with universal gas sensing chamber for sensing indicator compounds associated with meat safety

This study was conducted to evaluate the performance of a commercial electronic nose (Cyranose 320?) for sensing indicator compounds (ethanol and acetic acid) associated with spoiled beef. The present study reported the sensitivity of an array of 32 sensors to ethanol and acetic acid. Different vapor concentrations of ethanol (37, 100, 250 and 500 ppm) and acetic acid (38, 75, 100, 200 and 300 ppm) were tested to evaluate the performance of the commercial system. An in-house designed universal gas sensing and characterization system was coupled with the electronic nose system to generate the desired gas concentration. The raw smell print patterns were obtained and analyzed for individual and multiple detectors. Tukey’s multiple comparison technique was performed to analyze the response of individual detectors. Area above and below the baseline were selected as two features for pair wise comparison of the detectors. Different sensors showed different responses between various concentrations of gases. Analysis of multiple detectors was performed using linear and quadratic discriminant analysis (LDA and QDA) along with bootstrap. LDA along with bootstrap provided the highest total classification accuracies of 94.34 % between 100 and 200 ppm of acetic acid. QDA provided higher total classification accuracy of 89.69 % at lower concentration level of 38 and 75 ppm for acetic acid and 84.78 % between 37 and 100 ppm of ethanol. Hence, QDA was a better model of choice at lower concentrations. This study proved non-selective nature of sensors and showed that simultaneous use of multiple sensor information provided better classification accuracy for discriminating various gas concentrations as compared to using individual sensor output.     

MEMS tunable SOI waveguide Bragg grating filter with 1.3 THz tuning range for C-band 100 GHz DWDM optical network

A MEMS tunable integrated waveguide Bragg grating-based filter for C-band optical dense wavelength-division multiplexing (DWDM) network is presented and analyzed in this work. Waveguide Bragg grating being a notch filter in the transmission spectrum is used to realize a tunable filter by varying the applied voltages to the fixed–fixed beam loaded with this grating. The strain across the grating is enhanced by choosing MEMS beam configuration such that the metal electrode is the bottom-most layer of the composite fixed–fixed beam. Device dimensions are chosen to achieve a narrow full width half maximum of 0.77 nm, allowing filtering of adjacent channels of 100 GHz DWDM network. A large Bragg wavelength shift of 10.4 nm (1552.52–1562.92 nm) was achieved at 45.8 V actuation providing tuning for 14 DWDM channels with inter-channel cross talk below ? 21 dB, with tuning range of 1.3 THz.