Preparation and characterization of mesoporous γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> recovered from aluminum cans waste and its use in the dehydration of methanol to dimethyl ether

The present study includes synthesis of two γ-Al₂O₃ samples from waste aluminum cans using a simple precipitation method. Precipitation was carried out using two different precipitating agents (i.e. NaOH and NH₄OH). The two prepared alumina samples were characterized by means of X-ray diffraction (XRD) and N₂ adsorption–desorption techniques. Surface acidity of γ-Al₂O₃ samples was measured by adsorption of two different probe molecules (i.e. pyridine and dimethyl pyridine) followed by desorption measurements using thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. Catalytic activity of the two prepared alumina samples towards the dehydration of methanol (to dimethyl ether) was studied in a fixed bed reactor at 300 °C. For comparison reasons, commercial γ-Al₂O₃ sample was, also, tested for the same catalytic reaction under the same conditions. Results showed that the alumina sample prepared using NaOH as a precipitating agent exhibited a better catalytic activity and stability compared with that prepared using NH₄OH and showed a similar activity as the commercial γ-Al₂O₃ sample.     

Persistence of carbaryl in canal water

The presence of the insecticide carbaryl (Sevin) and its decomposition product 1-napthol was confirmed in irrigation and drainage canal water. However, their residues disappeared from the water 6 days after application.     

Chemometric application in identifying sources of organic contaminants in Langat river basin

Increasing urbanization and changes in land use in Langat river basin lead to adverse impacts on the environment compartment. One of the major challenges is in identifying sources of organic contaminants. This study presented the application of selected chemometric techniques: cluster analysis (CA), discriminant analysis (DA), and principal component analysis (PCA) to classify the pollution sources in Langat river basin based on the analysis of water and sediment samples collected from 24 stations, monitored for 14 organic contaminants from polycyclic aromatic hydrocarbons (PAHs), sterols, and pesticides groups. The CA and DA enabled to group 24 monitoring sites into three groups of pollution source (industry and urban socioeconomic, agricultural activity, and urban/domestic sewage) with five major discriminating variables: naphthalene, pyrene, benzo[a]pyrene, coprostanol, and cholesterol. PCA analysis, applied to water data sets, resulted in four latent factors explaining 79.0% of the total variance while sediment samples gave five latent factors with 77.6% explained variance. The varifactors (VFs) obtained from PCA indicated that sterols (coprostanol, cholesterol, stigmasterol, β-sitosterol, and stigmastanol) are strongly correlated to domestic and urban sewage, PAHs (naphthalene, acenaphthene, pyrene, benzo[a]anthracene, and benzo[a]pyrene) from industrial and urban activities and chlorpyrifos correlated to samples nearby agricultural sites. The results demonstrated that chemometric techniques can be used for rapid assessment of water and sediment contaminations.     

Spatial and temporal estimation of soil loss for the sustainable management of a wet semi-arid watershed cluster

The ungauged wet semi-arid watershed cluster, Seethagondi, lies in the Adilabad district of Telangana in India and is prone to severe erosion and water scarcity. The runoff and soil loss data at watershed, catchment, and field level are necessary for planning soil and water conservation interventions. In this study, an attempt was made to develop a spatial soil loss estimation model for Seethagondi cluster using RUSLE coupled with ARCGIS and was used to estimate the soil loss spatially and temporally. The daily rainfall data of Aphrodite for the period from 1951 to 2007 was used, and the annual rainfall varied from 508 to 1351 mm with a mean annual rainfall of 950 mm and a mean erosivity of 6789 MJ mm ha^?1 h^?1 year^?1. Considerable variation in land use land cover especially in crop land and fallow land was observed during normal and drought years, and corresponding variation in the erosivity, C factor, and soil loss was also noted. The mean value of C factor derived from NDVI for crop land was 0.42 and 0.22 in normal year and drought years, respectively. The topography is undulating and major portion of the cluster has slope less than 10°, and 85.3 % of the cluster has soil loss below 20 t ha^?1 year^?1. The soil loss from crop land varied from 2.9 to 3.6 t ha^?1 year^?1 in low rainfall years to 31.8 to 34.7 t ha^?1 year^?1 in high rainfall years with a mean annual soil loss of 12.2 t ha^?1 year^?1. The soil loss from crop land was higher in the month of August with an annual soil loss of 13.1 and 2.9 t ha^?1 year^?1 in normal and drought year, respectively. Based on the soil loss in a normal year, the interventions recommended for 85.3 % of area of the watershed includes agronomic measures such as contour cultivation, graded bunds, strip cropping, mixed cropping, crop rotations, mulching, summer plowing, vegetative bunds, agri-horticultural system, and management practices such as broad bed furrow, raised sunken beds, and harvesting available water using farm ponds and percolation tanks. This methodology can be adopted for estimating the soil loss from similar ungauged watersheds with deficient data and for planning suitable soil and water conservation interventions for the sustainable management of the watersheds.     

Evaluation of the efficiency of chlorpyrifos-ethyl remediation by Methylobacterium radiotolerans and Microbacterium arthrosphaerae using response of some biochemical biomarkers

Environmental Science and Pollution Research - This study reveals out detoxifying and antioxidant enzyme response of Gammarus pulex exposed/polluted to chlorpyrifos-ethyl insecticide before and...     

Efficient photocatalytic degradation of Rhodamine B dye using ZnO/graphitic C<Subscript>3</Subscript>N<Subscript>4</Subscript> nanocomposites synthesized by microwave

Semiconductor photocatalysis is a solution to issues of environmental pollution and energy shortage because photocatalysis can use solar energy to degrade pollutants. The photocatalytic activity can be improved by using composites of ZnO and other semiconductors. Here, composites of ZnO and polymeric graphite-like C₃N₄ (g-C₃N₄) with high photocatalytic activities were prepared by microwave synthesis. Products were characterized by X-ray diffraction, transmission electron microscopy, ultraviolet–visible and Fourier transform infrared spectroscopy. The photocatalytic degradation of Rhodamine B was tested under irradiation from a Xe lamp. Results show that adding graphite-like C₃N₄ promotes the photocatalytic activity of ZnO. Composites with 1.0 wt% g-C₃N₄ showed the best photodegradation efficiency, and the reaction average energy was approximately 33.71 kJ mol^?1.     

Correction to: Hydrogen production,storage, utilisation and environmental impacts: a review

Environmental Chemistry Letters -     

Integration of biogas systems into a carbon zero and hydrogen economy: a review

Environmental Chemistry Letters - The Ukraine conflict has put critical pressure on gas supplies and increased the price of fertilisers. As a consequence, biogas has gained remarkable attention as...