Response surface methodology analysis of the photocatalytic removal of Methylene Blue using bismuth vanadate prepared via polyol route

Visible-light driven photocatalyst bismuth vanadate (BiVO₄) photocatalyst was synthesized by the polyol route using ethylene glycol. The precipitate was washed, dried and calcined at 450℃ for 3 hr. The sample was characterized by X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), zeta potential, surface area (BET method) and band gap energy via diffuse reflectance spectroscopy (DRS). The synthesized BiVO₄ has a monoclinic phase with a surface area of 4.3 m²/g and a band gap energy of 2.46 eV. A majority of the particles were in the range of 90-130 nm as obtained from the particle size distribution histrogram. The efficiency of the sample as a visible-light driven photocatalyst was examined by photodegrading Methylene Blue (MB). The effects of some operational photodegradation parameters such as mass loading, initial dye concentration and pH were also examined. Experimental design methodology was applied by response surface modeling and optimization of the removal of MB. The multivariate experimental design was employed to develop a quadratic model as a functional relationship between the percentage removal of MB and three experimental factors (BiVO₄ loading, MB initial concentration and pH). The percentage removal of MB approached 67.21% under optimized conditions. In addition, a satisfactory goodness-of-fit was achieved between the predictive and the experimental results.     

Sludge granulation and e ciency of phase separator in UASB reactor treating combined industrial e uent

Sludge granulation and the effect of gas-liquid-solid separator （GLSS） design on the efficiency of upflow anaerobic sludge blanket （UASB） and upflow anaerobic sludge filter （UASF） reactors, operating at HRTs ranging from 3 to 12 h was investigated. VSS/TS ratio gradually increased in both the reactors with increasing sludge age （from 0.5 to more than 0.7 for UASB reactor and 0.012 to 0.043 for UASF reactor）. X-Ray diffraction analysis of the UASF sludge showed the presence of expanding clays revealing its additional absorption capability. Fuoraphyllite and albite precipitation related to excellular polymers of the microbial shell structure, showed the extended growth of microorganisms during sludge granulation. A gradual decrease （82%-69%） in COD removal with decreasing HRT was apparent in UASF reactor. In case of UASB reactor, this decrease was marginal because addition of GLSS device significantly improved （14%-20%） the overall efficiency of the UASB reactor. GLSS enhanced the efficiency of the UASB reactor by increasing the settleability of suspended particles and accelerating the coagulation of colloidal particles due to the velocity gradient.     

Dimethoate-induced oxidative stress and DNA damage in Oncorhynchus mykiss

The present study was conducted in order to investigate pro-oxidant activity of dimethoate in liver and brain tissues following sublethal pesticide exposure for 5, 15 and 30 d by using SOD, GPx, CAT enzyme activities and lipid peroxidation as biomarkers as well as DNA damaging potential via detecting% Tail DNA, Tail moment and Olive tail moment as endpoints in erythrocytes of Oncorhynchus mykiss in an in vitro experiment. Antioxidant enzyme activities were found to elicit two staged response which was an initial induction followed by a sharp inhibition in liver tissue while a sustained increase in GPx activity and slight stimulation in SOD activity were detected in brain tissue. Lipid peroxidation showed an ascending pattern throughout the exposure period in both tissues and a decreasing trend was determined in tissue protein levels which was proved to be positively correlated with duration. Similar findings were obtained from outcomes preferred to quantify DNA damage and TM was decided to reflect the extent of damage more sensitively because of determined positive correlation with concentrations applied. Considering these results, it can be concluded that oxidative stress condition evoked by dimethoate could not be responded effectively and genotoxic nature of pesticide was proven by determined clastogenic effect possibly via being an alkylation agent or stimulating the production of reactive species.     

Synthesis of Alkyd Resin from Non-Edible Jatropha Seed Oil

The kinetics of polyesterification of glycerol, phthalic anhydride and jatropha oil leading to the formation of alkyd resins were studied. A series of alkyd resins having different amount of jatropha oil viz., 40–80% have been prepared by employing two stage alcoholysis-polyesterification process. The extent of reaction and average degree of polymerisation were calculated from the end group analysis of the reaction mixture withdrawn at regular intervals of time. The initial reaction rates followed the second order kinetics and thereafter deviations were observed. An appreciable degree of conversion was noticed from the extent of the reaction which lies in the range of 49.5–62.5%. The average degree of polymerisation calculated in the region of deviation from second order suggested the occurrence of chain branching at relatively shorter intervals along the polymer chain. The second order rate constants were found to be of the order of 10⁻⁵ g (mg KOH)⁻¹ min⁻¹.     

A holistic approach for optimal design of air quality monitoring network expansion in an urban area

This paper presents an objective methodology for determining the optimum number of ambient air quality stations in a monitoring network. The methodology integrates the multiple-criteria method with the spatial correlation technique. The pollutant concentration and population exposure data are used in this methodology in different ways. In the first stage, the Fuzzy Analytic Hierarchy Process (FAHP) with triangular fuzzy numbers (TFNs) is used to identify the most desirable monitoring locations. The network configuration is then determined on the basis of the concept of sphere of influences (SOIs). The SOIs are dictated by a predetermined cutoff value (r_c) in the spatial correlation coefficients (r) between the pollutant concentrations at the monitoring stations identified from first step and the corresponding concentrations at neighboring locations in the region. Finally, the optimal station locations are ranked by using combined utility scores gained from the first and second steps. The expansion of air quality monitoring network of Riyadh city in Saudi Arabia is used as a case study to demonstrate the proposed methodology.     

Assessment of the impact of petroleum and petrochemical industries to the surrounding areas in Malaysia using mosses as bioindicator supported by multivariate analysis

Biomonitoring of multi-element atmospheric deposition using terrestrial moss is a well-established technique in Europe. Although the technique is widely known, there were very limited records of using this technique to study atmospheric air pollution in Malaysia. In this present study, the deposition of 11 trace metals surrounding the main petroleum refinery plant in Kerteh Terengganu (eastern part of peninsular Malaysia) has been evaluated using two local moss species, namely Hypnum plumaeforme and Taxithelium instratum as bioindicators. The study was also done by means of observing whether these metals are attributed to work related to oil exploration in this area. The moss samples have been collected at 30 sampling stations in the vicinity of the petrochemical industrial area covering up to 15 km to the south, north, and west in radius. The contents of heavy metal in moss samples were analyzed by energy dispersive x-ray fluorescence technique. Distribution of heavy metal content in all mosses is portrayed using Surfer software. Areas of the highest level of contaminations are highlighted. The results obtained using the principal components analysis revealed that the elements can be grouped into three different components that indirectly reflected three different sources namely anthropogenic factor, vegetation factor, and natural sources (soil dust or substrate) factor. Heavy metals deposited mostly in the distance after 9 km onward to the western part (the average direction of wind blow). V, Cr, Cu, and Hg are believed to have originated from local petrochemical-based industries operated around petroleum industrial area.     

Monitoring and assessment of heavy metal/metalloid concentration by inductively coupled plasma mass spectroscopy (ICP-MS) method in Gonyeli Lake,Cyprus

The presence of heavy metals/metalloids in the ecosystem has been an increasing ecological and global public health concern due to their potential to cause adverse health effects. For this reason, the accumulation of some heavy metals such as Cr, Mn, Ni, Cu, As, Cd, Pb was assessed by way of ICP-MS in water, sediment and fish (Cyprinus carpio) sampled from Gonyeli Lake, North Cyprus. The results showed that these metals/metalloids are found widespread throughout the study area. In water, most concentrated element was manganese with 92.1 ppb and least concentrated was lead with 0.914 ppb. In sediment, copper had the highest concentration with 613 ppm, and cadmium the lowest with 1.57 ppm. In fish tissues (muscle and gills), the most concentrated element was manganese with 12.5 ppm and the least concentrated cadmium with 0.017 ppm. These results indicate that future remediation efforts are indispensable for the rehabilitation of the lake.     

Analyzing riparian forest cover changes along the Firniz River in the Mediterranean City of Kahramanmaras in Turkey

Riparian forests adjacent to surface water are important transitional zones which maintain and enrich biodiversity and ensure the sustainability in a forest ecosystem. Also, riparian forests maintain water quality, reduce sediment delivery, enhance habitat areas for aquatic life and wildlife, and provide ecological corridors between the upland and the downstream. However, the riparian ecosystems have been degraded mainly due to human development, forest operations, and agricultural activities. In order to evaluate the impacts of these factors on riparian forests, it is necessary to estimate trends in forest cover changes. This study aims to analyze riparian forest cover changes along the Firniz River located in Mediterranean city of Kahramanmaras in Turkey. Changes in riparian forest cover from 1989 to 2010 have been determined by implementing supervised classification method on a series of Landsat TM imagery of the study area. The results indicated that the classification process applied on 1989 and 2010 images provided overall accuracy of 80.08 and 75 %, respectively. It was found that the most common land use class within the riparian zone was productive forest, followed by degraded forest, agricultural areas, and other land use classes. The results also indicated that the areas of degraded forest and forest openings increased, while productive forest and agricultural areas decreased between the years of 1989 and 2010. The amount of agricultural areas decreased due to the reduction in the population of rural people. According to these results, it can be concluded that special forest management and operation techniques should be implemented to restore the forest ecosystem in riparian areas.     

Monitoring the drastic growth of ship breaking yards in Sitakunda: a threat to the coastal environment of Bangladesh

The vast coastal and marine resources that occur along the southern edge of Bangladesh make it one of the most productive areas of the world. However, due to growing anthropogenic impacts, this area is under considerable environmental pressure from both physical and chemical stress factors. Ship breaking, or the dismantling and demolition of out-of-service ocean-going vessels, has become increasingly common in many coastal areas. To investigate the extent of ship breaking activities in Bangladesh along the Sitakunda coast, various spatial and non-spatial data were obtained, including remote sensing imagery, statistical records and published reports. Impacts to coastal and marine life were documented. Available data show that ship breaking activities cause significant physical disturbance and release toxic materials into the environment, resulting in adverse effects to numerous marine taxonomic groups such as fish, mammals, birds, reptiles, plants, phytoplankton, zooplankton and benthic invertebrates. Landsat imagery illustrates that the negatively impacted coastal area has grown 308.7 % from 367 ha in 1989 to 1,133 ha in 2010. Physicochemical and biological properties of coastal soil and water indicate substantially elevated pollution that poses a risk of local, regional and even global contamination through sea water and atmospheric transport. While damage to the coastal environment of Bangladesh is a recognized hazard that must be addressed, the economic benefits of ship breaking through job creation and fulfilling the domestic demand for recycled steel must be considered. Rather than an outright ban on beach breaking of ships, the enterprise must be recognized as a true and influential industry that should be held responsible for developing an economically viable and environmentally proactive growth strategy. Evolution of the industry toward a sustainable system can be aided through reasonable and enforceable legislative and judicial action that takes a balanced approach, but does not diminish the value of coastal conservation.