Effect of UV-A radiation as an environmental stress on the development,longevity, and reproduction of the oriental armyworm, <Emphasis Type="Italic">Mythimna separata</Emphasis> (Lepidoptera: Noctuidae)

The ultraviolet light (UV-A) range of 320–400 nm is widely used as light trap for insect pests. Present investigation was aimed to determine the effect of UV light-A radiation on development, adult longevity, reproduction, and development of F₁ generation of Mythimna separata. Our results revealed that the mortality of the second instar larvae was higher than the third and fourth instar larvae after UV-A radiation. As the time of UV-A irradiation for pupae prolonged, the rate of adult emergence reduced. Along with the extension of radiation time decreased the longevity of adult females and males. However, the radiation exposure of 1 and 4 h/day increased fecundity of female adults, and a significant difference was observed in a 1 h/day group. The oviposition rates of female adults in all the treatments were significantly higher than the control. In addition, UV-A radiation treatments resulted in declined cumulative survival of F₁ immature stages (eggs, larvae, and pupae). After exposure time of 4 and 7 h/day, the developmental periods of F₁ larvae increased significantly, but no significant effects on F₁ pupal period were recorded.     

Experimental study of cross-flow wet electrostatic precipitator

This paper reports development and testing of a novel cross-flow wet electrostatic precipitator (WESP), recently patented at Ohio University, that utilizes vertical columns of permeable material in the form of polypropylene ropes placed in a cross-flow configuration within a flue gas stream. The cross-flow design has large surface area, which provides scrubbing action; therefore, it has the potential for removing multiple pollutants, including particulates, gases, vapors, and mists. In this new method, the ropes are kept wet by the liquid (water) introduced from the top of the cells running downward on the ropes by capillary action, making the permeable materials act as the ground electrode for capturing particles from the flue gas. Preliminary testing has shown an efficiency of well above 80% using two cells and three sets of discharge electrodes. Since the material of construction is primarily corrosion-resistant polymeric material, both weight and cost reductions are expected from this new design.

Implications: The newly invented cross-flow WESP exhibit particulate collection efficiency of well above 80% when introduced in particulate-laden exhaust flow. This value was obtained using a two cells and three discharge electrodes configuration. The electric field strength has a substantial effect on the collection efficiency. Also, the pressure drop test results indicate that there is a potential to increase the collection area, which, in turn, will increase the collection efficiency further.     

Visible light photocatalytic water disinfection and its kinetics using Ag-doped titania nanoparticles

The UN estimated about five million deaths every year due to water-borne diseases, accounting from four billion patients. Keeping in view, the ever increasing health issues and to undermine this statistics, a reliable and sustainable water-treatment method has been developed using visible light for water treatment. titania nanoparticles (NPs) have been synthesized successfully by a more applicable method Viz: liquid impregnation (LI) method. The bacterial death rate by photocatalysis under visible light was studied by employing a typical fluorescent source and was found to follow pseudo first-order reaction kinetics. The nanoparticles were characterized using X-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive X-ray spectroscopy to deduce their size range, surface morphology, and elemental compositions, respectively. Among all the prepared grades, 1 % Ag–TiO₂ was found to be a very effective photocatalytic agent against Escherichia coli. The resulted photoinactivated data were also evaluated by different empirical kinetic models for bacterial inactivation. Hom, Hom-power, Rational, and Selleck models were not able to explain the disinfection kinetics but modified-Hom model fitted best with the experimentally obtained data by producing a shoulder, log-linear, and a tail region.     

An electrochemical nanocomposite modified carbon paste electrode as a sensor for simultaneous determination of hydrazine and phenol in water and wastewater samples

In this study, we report preparation of a high sensitive electrochemical sensor for determination of hydrazine in the presence of phenol in water and wastewater samples. In the first step, we describe synthesis and characterization of ZnO/CNTs nanocomposite with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). In the second step, application of the synthesis nanocomposite describes the preparation of carbon paste electrode modified with n-(4-hydroxyphenyl)-3,5-dinitrobenzamide as a high sensitive and selective voltammetric sensor for determination of hydrazine and phenol in water and wastewater samples. The mediated oxidation of hydrazine at the modified electrode was investigated by cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy (EIS). Also, the values of catalytic rate constant (k) and diffusion coefficient (D) for hydrazine were calculated. Square wave voltammetry (SWV) of hydrazine at the modified electrode exhibited two linear dynamic ranges with a detection limit (3σ) of 8.0 nmol L^?1. SWV was used for simultaneous determination of hydrazine and phenol at the modified electrode and quantitation of hydrazine and phenol in some real samples by the standard addition method.     

Electrochemical treatment of domestic wastewater using boron-doped diamond and nanostructured amorphous carbon electrodes

The performance of the electrochemical oxidation process for efficient treatment of domestic wastewater loaded with organic matter was studied. The process was firstly evaluated in terms of its capability of producing an oxidant agent (H₂O₂) using amorphous carbon (or carbon felt) as cathode, whereas Ti/BDD electrode was used as anode. Relatively high concentrations of H₂O₂ (0.064 mM) was produced after 90 min of electrolysis time, at 4.0 A of current intensity and using amorphous carbon at the cathode. Factorial design and central composite design methodologies were successively used to define the optimal operating conditions to reach maximum removal of chemical oxygen demand (COD) and color. Current intensity and electrolysis time were found to influence the removal of COD and color. The contribution of current intensity on the removal of COD and color was around 59.1 and 58.8 %, respectively, whereas the contribution of treatment time on the removal of COD and color was around 23.2 and 22.9 %, respectively. The electrochemical treatment applied under 3.0 A of current intensity, during 120 min of electrolysis time and using Ti/BDD as anode, was found to be the optimal operating condition in terms of cost/effectiveness. Under these optimal conditions, the average removal rates of COD and color were 78.9?±?2 and 85.5?±?2 %, whereas 70 % of total organic carbon removal was achieved.     

Source apportionment of surfactants in marine aerosols at different locations along the Malacca Straits

This study aims to determine the source apportionment of surfactants in marine aerosols at two selected stations along the Malacca Straits. The aerosol samples were collected using a high volume sampler equipped with an impactor to separate coarse- and fine-mode aerosols. The concentrations of surfactants, as methylene blue active substance and disulphine blue active substance, were analysed using colorimetric method. Ion chromatography was employed to determine the ionic compositions. Principal component analysis combined with multiple linear regression was used to identify and quantify the sources of atmospheric surfactants. The results showed that the surfactants in tropical coastal environments are actively generated from natural and anthropogenic origins. Sea spray (generated from sea-surface microlayers) was found to be a major contributor to surfactants in both aerosol sizes. Meanwhile, the anthropogenic sources (motor vehicles/biomass burning) were predominant contributors to atmospheric surfactants in fine-mode aerosols.     

Applying Raman spectroscopy to the assessment of the biodegradation of industrial polyurethanes wastes

Polyether-based polyurethanes (PBP) are extremely problematic polymers due to their long persistence in the environment. Moreover, the assessment of PBP biodegradation remains biased due to the inability of conventional methods to determine how their diverse subunits are degraded. To improve our knowledge of PBP biodegradation, we used Raman spectroscopy to identify patterns of PBP biodegradation. Specifically, PBP biodegradation was assessed using a microbial inoculum isolated from an industrial soil in which polyurethanes have been buried for 40 years. During a 28-day biodegradation assay, the PBP biodegradation level reached 27.5 % (w/w), in addition to undergoing profound alteration of the PBP composition as identified by chemical analyses. After microbial degradation, Raman analyses revealed the disappearance of the polymer’s amorphous region, which contains a high polyol content, whereas the isocyanate-rich crystalline regions were preserved. The use of Raman spectroscopy appears to be a particularly useful tool to enhance our assessment of polymer biodegradation.     

Removal of arsenate from groundwater by electrocoagulation method

Purpose

Arsenic, a toxic metalloid in drinking water, has become a major threat for human beings and other organisms. In the present work, attempts have been made to remove arsenate from the synthetic as well as natural water of Ballia district, India by electrocoagulation method. Efforts have also been made to optimize the various parameters such as initial arsenate concentration, pH, applied voltage, processing time, and working temperature.

Method

Electrocoagulation is a fast, inexpensive, selective, accurate, reproducible, and eco-friendly method for arsenate removal from groundwater. The present paper describes an electrocoagulation method for arsenate removal from groundwater using iron and zinc as anode and cathode, respectively.

Results

The maximum removal of arsenate was 98.8% at 2.0?mg?L^?1, 7.0, 3.0?V, 10.0?min, and 30°C as arsenate concentration, pH, applied voltage, processing time, and working temperature, respectively. Relative standard deviation, coefficient of determination (r ²), and confidence limits were varied from 1.50% to 1.59%, 0.9996% to 0.9998%, and 96.0% to 99.0%, respectively. The treated water was clear, colorless, and odorless without any secondary contamination. The developed and validated method was applied for arsenate removal of two samples of groundwater of Ballia district, U.P., India, having 0.563 to 0.805?mg?L^?1, arsenate concentrations.

Conclusions

The reported method is capable for the removal of arsenate completely (100% removal) from groundwater of Ballia district. There was no change in the groundwater quality after the removal of arsenate. The treated water was safe for drinking, bathing, and recreation purposes. Therefore, this method may be the choice of arsenate removal from natural groundwater.     

Indigenous soil bacteria with the combined potential for hydrocarbon consumption and heavy metal resistance

Introduction  

Transconjugant bacteria with combined potential for hydrocarbon utilization and heavy metal resistance were suggested by earlier investigators for bioremediation of soils co-contaminated with hydrocarbons and heavy metals. The purpose of this study was to offer evidence that such microorganisms are already part of the indigenous soil microflora.     

Degradation of ampicillin antibiotic in aqueous solution by ZnO/polyaniline nanocomposite as photocatalyst under sunlight irradiation

PURPOSE AND METHOD: ZnO/polyaniline nanocomposite in core-shell structure was prepared by the synthesis and adsorption of polyaniline chains on the structure of ZnO nanoparticles. Fourier transform infrared and ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction patterns, field emission scanning electron microscopy, and transmission electron microscopy were used to characterize the composition and structure of the nanocomposite. The nanocomposite was used as an active photocatalyst for photodegradation and removal of ampicillin in aqueous solution. RESULTS: UV-Vis spectroscopy studies showed that ZnO/polyaniline nanocomposite absorbs visible light irradiation as well as ultraviolet spectrum, and therefore, it can be photoactivated under visible and ultraviolet lights. The photocatalytic activity of ZnO/polyaniline nanocomposite in degradation of ampicillin molecules in aqueous solution under natural sunlight irradiation was evaluated and compared with that of ZnO nanoparticles and pristine polyaniline. The ZnO/polyaniline core-shell nanocomposite exhibited higher photocatalytic activity compared to ZnO nanoparticles and pristine polyaniline. The effect of operating conditions (pH, ZnO/polyaniline nanocomposite dosage, and ampicillin concentration) in the photocatalytic degradation of ampicillin using ZnO/polyaniline nanocomposite was investigated. The optimum conditions for maximum efficiency of ampicillin degradation under 120 min sunlight irradiation were found as 10 mg L(-1) dosage of ZnO/polyaniline nanocomposite, ampicillin concentration of 4.5 mg L(-1), and solution pH?=?5. Under optimum operating conditions, degradation efficiency was reached to 41% after 120 min of exposure to the sunlight irradiation.