INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY (IJEST)
Year:2014 | Volume:11 | Issue:4|Papers Count:30

The use of natural coagulant protein in drinking water treatment has been discussed for a long time, though the method is still not in practice, probably due to limited knowledge and availability of material. In the present work, different Mustard varieties were tested for the presence of coagulant protein compared with Moringa seed extract and their potential application in water treatment. The coagulation activity of the protein extract was measured using synthetic clay solution as well as water from pond. The protein content was determined by Bradford method, molecular mass determined by Sodium dodecyl sulfate–polyacrylamide gel electrophoresis, and peptide sequence was analyzed by Mass spectrometry. Extract of Mustard (large) and Moringa seed showed coagulation activity of @70 and @85% after 90 min, respectively. Interestingly, seed extracts from other Mustard varieties had coagulation activity after heat activation at 95oC for 5 h. However, the coagulation activity of Mustard seed extract against turbid pond water was higher (@60%) compared to Moringa seed extract (@50%). The peptide sequence analysis of 6.5 and 9 kDa proteins was found to be homologous to Moringa coagulant protein and napin 3, respectively. To our knowledge, this could be the first report on Mustard seed having coagulant protein. The coagulation activity of Mustard (large) against highly turbid pond water suggested that it could be a potential natural coagulant for water treatment.

Zero-valent iron (Fe0), as an alternative iron source, was evaluated to activate persulfate (PS) to degrade acetaminophen (APAP), a representative pharmaceutically active compound in water. Effects of key factors in the so-called Fe0/PS process, including Fe0 dosage, initial pH, temperatures and chelating agents, were studied. Under all the conditions tested, the APAP degradation followed a pseudo-first-order kinetics pattern. The degradation efficiency of APAP was highest when the Fe0 to PS molar ratio increased to 1:1, and the degradation rate constant and removal were 23.19×10-3 min-1 and 93.19%, respectively. Comparing with Fe2+, Fe0 served as an alternative iron source that can gradually release Fe2+ into water, thereby consistently activating PS to produce sulfate radicals. The Fe0/PS system was effective in a broader pH range from 3 to 8.5. Heat could facilitate production of sulfate radicals and enhance the APAP degradation in the Fe0/PS system. High reaction temperature also improved the Fe2+/PS oxidation of APAP. Finally, sodium citrate (a chelating agent) at an appropriate concentration could improve the APAP degradation rate in the Fe2+/PS and Fe0/PS system. The optimal molar ratio of Fe0 to citrate depended on solution pH. Our results demonstrated that Fe0 was an alternative iron source to activate PS to degrade APAP in water.

To effectively biodegrade organophosphorus pesticides residue in environment, we constructed a genetically engineered bacterium (GEB) which can not only emit red fluorescence but also degrade organophosphorus pesticides residue, and this GEB can commit suicide when required. Two genes with different functions were placed under the control of different promoters. One was the dual gene expression vector pL-DsRed–pL-OPH in which genes coding for DsRed and organophosphorus hydrolase were independently placed downstream of two pL promoters. These genes could be expressed freely as long as the GEB was alive. The other was the conditional suicide plasmid pDS containing two suicide cassettes designed to induce bacteria to commit suicide when they detect arabinose. The lethal gene used in the suicide plasmid was the nuclease gene of Serratia marcescens without the leader-coding sequence. This was put under the control of the T7 promoter. Applying this type of secure GEB could potentially be a less hazardous environmental strategy in degrading pesticides and contamination.

Diversity and abundance of five species of epiphytic lichens were assessed in Kolkata, India. Significant correlation between abundance of lichen species and volume of vehicular traffic suggests atmospheric pollution load in urban region. Parmelia caperata (L.) Ach. and Graphis scripta (L.) Ach. exhibited higher abundance among the five species studied indicating their higher level of tolerance to air pollution. Significant correlations (p<0.05) between levels of heavy traffic and both diversity and abundance of all lichen species were also observed. These findings indicate a potential threat to the survival of the lichen communities in Kolkata. Study further deals with quantifying the effectiveness of lichen species in accumulating metallic elements like Pb, Zn, and Cu. This was achieved by analyzing the most abundant lichen species (Parmelia caperata) collected from nine different sites in winter, summer, and monsoon seasons. Metal content in lichen thalli, as analyzed by AAS, shows their elevated levels with the order Pb>Zn>Cu. Relationship between metal content and volume of vehicular traffic suggests that co-associated, metallic elements are emitted as vehicle-derived pollutants as well as diffuse industrial emissions. Accumulation of these metals is higher in winter which is proportionate with the higher degree of metabolism due to higher humidity in this season. Study also demonstrates the dynamics of metal uptake by the lichen at different sites influenced with different degree of vehicular traffic. Overall results confirm suitability of lichen with their potential role in sequestration of atmospheric metal contamination.

This study presents a landslide susceptibility assessment for the Caspian forest using frequency ratio and index of entropy models within geographical information system (GIS). Firstly, the landslide locations were identified in the study area from interpretation of aerial photographs and multiple field surveys. 72 cases (70%) out of 103 detected landslides were randomly selected for modelling and the remaining 31 (30%) cases were used for the model validation. The landslide conditioning factors, including slope degree, slope aspect, altitude, lithology, rainfall, distance to faults, distance to streams, plan curvature, topographic wetness index (TWI), stream power index (SPI), sediment transport index (STI), normalized difference vegetation index (NDVI), forest plant community, crown density, and timber volume were extracted from the spatial database. Using these factors, landslide susceptibility and weights of each factor were analyzed by frequency ratio and index of entropy models. Results showed that the high and very high susceptibility classes cover nearly 50% of the study area. For verification, the ROC (receiver operating characteristic) curves were drawn and the areas under the curve (AUC) calculated. The verification results revealed that the index of entropy model (AUC=75.59%) is slightly better in prediction than frequency ratio model (AUC=72.68%). The interpretation of the susceptibility map indicated that NDVI, altitude, and rainfall play major roles in landslide occurrence and distribution in the study area. The landslide susceptibility maps produced from this study could assist planners and engineers for reorganizing and planning of future road construction and timber harvesting operations.

To evaluate the effect of olive mill wastewater (OMW) application on soil hydraulic and transport properties, two treatment sites, which had been irrigated with OMW for 5 and 15 years, and one control site being irrigated with freshwater were compared. The transport and leaching experiment results showed that a portion of the total soil water was available for transport processes while the remaining of the soil water was considered immobile and not readily accessible for solutes. The separation in water fractions of different mobilities was surprisingly consistent among OMW treatments. The bromide recovery rate decreased with the application of OMW showing that tracer molecules became trapped within immobile water phases. The application of OMW increased significantly the soil water-holding capacity, whereas the soil hydraulic conductivity in the near saturation range decreased significantly with long-term OMW application. The soil irrigated with OMW had significantly higher organic matter content, lower bulk density and relatively higher total porosity, but lower macroporosity than that of control sites. We concluded that the soil was increasingly coated with complex organic molecules originating from OMW, as a result, solute exchange between inter- and intrasoil aggregate water was hindered. Although OMW could cause soil and water pollution, its use in agriculture is promoted because of high nutrients and organic matter contents.

The Vinto Sb–Sn smelter (Oruro, Bolivia) has been linked to arsenic and heavy metal pollution in air, soils, residual waters of the smelter, and hair and urine of workers, but crop concentrations had not been assessed previously. In this article, alfalfa, onions, and carrots, separated into roots and shoots, were analyzed for As and Pb, together with corresponding soil samples. The aim was to assess the environmental distribution and potential health impacts of these toxic elements and to compare them to levels observed at other sites around the world. As and Pb concentrations in all analyzed crop samples exceed the FAO/WHO, UK or Chilean limits by 1.5–2 orders of magnitude and As health risk indices were 286 (carrot) and 651 (onion), showing that the potential health risk due to consumption of these products is extremely high. As and Pb soil–plant transfer factors are similar to other contaminated sites around the world, but daily intake and health risk index for As are much higher in Vinto area due to very high concentrations in soils. Arsenic and lead soil and crop concentrations suggest increasing trends toward VMC. Correlations are significant for Pb in some crop fractions, but not for As, possibly due to considerable geogenic contributions to soil As in the area. In future surveys, larger numbers of soil and crop samples should be analyzed, and additional analyses should be carried out to distinguish anthropogenic and geogenic sources of As and Pb in soils and crops in the area.

This work investigates the influence of compression ratio on the performance and emissions of a diesel engine using biodiesel (10, 20, 30, and 50%) blended-diesel fuel. Test was carried out using four different compression ratios (17.5, 17.7, 17.9 and 18.1). The experiments were designed using a statistical tool known as design of experiments based on response surface methodology. The resultant models of the response surface methodology were helpful to predict the response parameters such as brake specific fuel consumption, brake thermal efficiency, carbon monoxide, hydrocarbon and nitrogen oxides. The results showed that best results for brake thermal efficiency and brake specific fuel consumption were observed at increased compression ratio. For all test fuels, an increase in compression ratio leads to decrease in the carbon monoxide and hydrocarbon emissions while nitrogen oxide emissions increase. Optimization of parameters was performed using the desirability approach of the response surface methodology for better performance and lower emission. A compression ratio 17.9, 10 % of fuel blend and 3.81 kW of power could be considered as the optimum parameters for the test engine.

Cathode ray tube funnel glass is an environmentally problematic relict of old television sets. In particular, landfilling of this material is strongly discouraged because of its high lead content. However, recovery of this toxic lead could prevent its release into the environment and allow its reuse. In this research, lead was separated from the glass matrix by a chloride volatilization process. Melting of the funnel glass together with CaCl2 resulted in the volatilization of 80% of lead at 1,000oC. The use of NaCl as a chlorination agent yielded less volatile lead, while poly (vinyl chloride) and gaseous HCl proved to be ineffective chlorination agents. The differences in the chlorination agent efficiencies could be attributed to differences in the corresponding formation of silicates. Energy-dispersive X-ray spectroscopy showed that diffusion plays an important role in the volatilization of PbCl2.

The objectives of this study were to determine the selected physicochemical properties of two biochars, one commercially produced from rice husks and the other from oil palm empty fruit bunches, and to evaluate their adsorption capacities for Zn, Cu, and Pb using a batch equilibrium method. The results showed that there was no significant difference between the carbon content of biochars formed from empty fruit bunches (EFBB) and rice husks (RHB). However, the EFBB did present higher quantities of O, H, S, N, and K, compared to the RHB. Although the EFBB had a much lower surface area than the RHB, the former adsorbed much more Zn, Cu, and Pb than the RHB. The higher adsorption capacity of the EFBB over the RHB was a result of the EFBB having higher amounts of oxygen-containing functional groups, a higher molar ratio of O/C, and a higher polarity index [(O+N)/C]. This suggests that the biochar’s chemical properties were more important than its surface area in the adsorption of Zn, Cu, and Pb.

Silver nanoparticles (Ag NPs) were synthesized in situ, using a one-step green methodology with Camellia sinensis (green tea) aqueous extract as reducing agent, and supported on a carbonaceous material (Ag-CM), originated from the pyrolysis of sewage sludge. UV–Vis spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Brunauer–Emmet–Teller were used to characterize the nanocomposite. Ag-CM composite exhibited very good catalytic activity in the degradation process of methylene blue (MB) dye in aqueous solution without using sunlight or UV radiation. Batch kinetic and isothermal experiments, using 30 mg/L MB solution, showed that Ag-CM composite removed near to 91% of MB in 9 h, whereas the carbonaceous material alone removed only 60% in 30 h. Experimental data were adjusted to different kinetic and isotherms models, where both materials fit the second-order and Langmuir–Freundlich models, respectively; therefore, a chemisorption mechanism probably occurs in these heterogeneous materials.

The adsorption of cadmium from simulated mining wastewater by coal waste (CW) and calcination-modified coal waste (MCW) was investigated. Effects of pH, initial concentration, particle size of adsorbent, adsorbent dosage and temperature were studied in batch experiments. The adsorption efficiency for cadmium increased with increasing pH, and the optimum pH for cadmium adsorption onto MCW and CW was 6.0 and 6.5, respectively. Kinetic experiments showed that the adsorption equilibrium was reached within 120 min and followed pseudo-second-order model well. The adsorption isotherm data fit Langmuir and Freundlich models, and the adsorption capacity of cadmium on the two adsorbents increased with increasing temperature from 298 to 318 K. MCW had a higher adsorption capacity of cadmium than CW, because calcination treatment can make CW to have more loose structure and higher specific surface area. Thermodynamic parameters, the Gibbs free energy change (DG0), enthalpy change (DH0) and entropy change (DS0), were calculated and the results showed that the adsorption of cadmium on CW and MCW was spontaneous and endothermic. Fourier transform infrared studies indicated silanol and aluminol groups were responsible for cadmium binding. The desorption results indicated that the two adsorbents could be used repeatedly at least three times without significant decrease in the adsorption capacity for cadmium. The results suggested that modified CW could have high potential as low-cost adsorbent for cadmium removal.

In the present work, H2S of crude oil was removed via a two-step method including stripping followed by adsorption. First, ZnO/MCM-41 adsorbents containing 5, 17.5 and 30 wt% of zinc were synthesized and characterized using XRD and nitrogen physisorption. Then, these materials were used as adsorbents for the removal of the H2S stripped from crude oil. At second step, the H2S of crude oil was extracted to gas phase by hot stripping. The obtained extract was collected in a storage tank for the subsequent H2S adsorption process. A three factor Box-Behnken design with five center points and one response was performed for the optimization of adsorption of H2S. The influence of process parameters and their interactional effects on the adsorption of H2S were analyzed using the obtained adsorption experimental data. A model including three important factors, i.e. temperature, space velocity and amount of supported zinc and their interactions was developed to generate the optimum condition. The point of Zn=30 wt%, T=300oC and Space velocity= 3000 hr-1 had the optimum point with the highest breakpoint time (tbp = 973 min).

Textile effluents are considered among the most polluted wastewaters all over the world. Among different textile processes, dyeing is the operation that produces the most important amounts of chemical pollution. Many studies have been carried out toward the treatment of these hazardous effluents, and a variety of techniques have been applied for this aim. In this work, the effluents coming from different steps of the dyeing cycle were treated following different mixtures of baths using membrane technology. Nanofiltration (NF) experiments were performed for color removal, but membrane fouling still a major limitation. To enhance NF performances, microfiltration (MF) was carried out as pretreatment to NF. The results showed almost above 99% of color and turbidity removal and also an important decrease in COD, chloride and salts contents with an improvement in the MF and NF stabilized fluxes of different mixtures compared to that corresponding to the dyeing effluent treated separately. In order to accomplish a full reuse cycle, dyeing experiments were performed using the combined system (MF/NF) permeates. Results were evaluated regarding total color difference between samples and a standard test done with fresh water.

Remediation of heavy-metal-contaminated sediment is often hampered by the availability of heavy metals to the added chemical agents because the heavy metals are often shielded by the sediment matrix. Effective heavy-metal extraction technique becomes an important factor in enhancing the treatment efficiency. A novel extraction/washing technique utilizing chelating agent and elevated pressure in consecutive cycles of compression and decompression has been developed for heavy-metal-contaminated sediment washing in the presence of chelating agent. In this study, the optimal operational conditions of pressure-assisted cyclic washing of Cu-contaminated sediments (initial Cu concentration =23.177 mg/kg) were determined in a laboratory-scale system. The control factors included applied pressure level, washing time, applied chelant [ethylenediamine-tertraacetic (EDTA)] concentration (0.01–0.5 M), pressure times, and application of consecutive batches washing. Results from the bench-scale study showed that up to 70% of Cu can be removed from the sediments when 10 atm of pressure was applied for washing. The efficiency dropped to 55% when the pressure dropped to 6 atm. Under the same operational conditions, the optimal cyclic washing time was 60 min. Results from the particle size analyses indicate that the mean particle size dropped from 100 to 50 mm after the pressure-assisted cyclic washing. Thus, cyclic pressure caused the fracture of sediment aggregates resulting in the exposure of Cu to chelating agents. With the assistance of pressure cyclic system, the total washing time and the amount of added chemical agent used can be significantly reduced.

Adsorption characteristics of water hyacinth roots powder for the removal of Indosol Dark-blue GL dye were investigated in batch mode. Operating variables, such as initial solution pH, presence of detergent, adsorbent dosage, initial concentration and contact time were studied. The results showed that the adsorption of dye increased with increasing the initial concentration and contact time. The adsorption is highly pH dependent and adsorption capacity increased with decrease in pH. Kinetic study revealed that the uptake of Indosol Dark-blue GL was very rapid within the first 15 minutes and equilibrium time was independent of initial concentration. Batch equilibrium experiments were carried out at different pH and found that equilibrium data fitted well to Langmuir isotherm model. The maximum sorption capacity of the adsorbent was found as 86 mg g-1 at pH 3 which reduced to 64 mg g-1 at pH 5. Presence of detergent reduced the sorption capacity of the adsorbent significantly. Using equilibrium and kinetic data, the forward and backward rate constants were determined from the Unified approach model. Desorption study revealed that the dye can be recovered by swing the pH from low to high.

The demand for accurate predictions of sea level fluctuations in coastal management and ship navigation activities is increasing. To meet such demand, accessible high-quality data and proper modeling process are critically required. This study focuses on developing and validating a neural methodology applicable to the short-term forecast of the Caspian Sea level. The input and output data sets used contain two time series obtained from Topex/Poseidon and Jason-1 satellite altimetry missions from 1993 to 2008. The forecast is performed by multilayer perceptron network, radial basis function, and generalized regression neural networks. Several tests of different artificial neural network (ANN) architectures and learning algorithms are carried out as alternative methods to the conventional models to assess their applicability for estimating Caspian Sea level anomalies. The results derived from the ANN are compared with observed sea level values and with the forecasts calculated by a routine autoregressive moving average (ARMA) model. Different ANNs satisfactorily provide reliable results for the short-term prediction of Caspian Sea level anomalies. The root mean square errors of the differences between observations and predictions from artificial intelligence approaches can be significantly reduced by about 50% compared with ARMA techniques.

Heavy metals are a threat to human health and ecosystem. These days, great deal of attention is being given to green technologies for purification of water contaminated with heavy metal ions. Biosorption is one among such emerging technologies, which utilizes naturally occurring waste materials to sequester heavy metals from wastewater. Cadmium has hazardous impact on living beings; therefore, its removal through green and economical process is an important task. The aim of the present study was to utilize the locally available Portulaca oleracea plant biomass as an adsorbent for cadmium removal from aqueous solution. The biomass was obtained after drying and grinding the portulaca leaves and stem. No chemical treatment was done on the adsorbent so that it remained green in a true sense. Batch experiments were performed at room temperature. The critical parameters studied were effects of pH, contact time, initial metal ion concentration and adsorbent dose on the adsorption of cadmium. The maximum adsorption was found to be 72%. The kinetic data were found to best fit the pseudo-second-order equation. High adsorption rates were obtained in the initial 45 min, and adsorption equilibrium was then gradually achieved in about 100 min. Adsorption increased with increase in pH for a range 2 and 6. The equilibrium adsorption results closely followed both the Langmuir and Freundlich isotherms. The values of constants were calculated from isotherms. Results indicated that portulaca plant biomass could be developed as a potential material to be used in green water treatment devices for removal of metal ions.

Chitosan was cross-linked using glutaraldehyde in the presence of magnetite. The resin obtained was chemically modified through the reaction with tetraethylenepentamine ligand. The obtained resin was loaded with Mo (VI) and investigated. The adsorption characteristics of the obtained resin toward As (V) at different experimental conditions were investigated by means of batch and column methods. The resin showed high affinity and fast kinetics for the adsorption of As (V) where an uptake value of 1.30 mmol g-1 was reported in 6 min at 25oC. Various parameters such as pH, agitation time, As (V) concentration and temperature had been studied. The kinetics and thermodynamic behavior of the adsorption reaction were defined. These data indicated an endothermic and spontaneous adsorption process and kinetically followed pseudo-second-order model, Fickian diffusion low and Elovich equation. Breakthrough curves for the removal of As (V) were studied at different flow rates and bed heights. The critical bed height for the studied resin column was found to be 0.656 cm at flow rate of 4 mL min-1. The mechanism of interaction between As (V) and resin’s active sites was discussed. Regeneration and durability of the loaded resin toward the successive cycles were also clarified.

Heavy metal ions from single and ternary systems of Pb (II), Cu (II), and Ni (II) adsorbed by calix [4] resorcinarenes in water–chloroform extraction were studied. Comparison was made of calix [4] resorcinarenes, 2, 8, 14, 20-tetraundecyl calix [4] resorcinarene-4, 6, 10, 12, 16, 18, 22, 24-octol, and diethylaminomethyl-calix [4] resorcinarene, 5, 11, 17, 23-tetra (diethylaminomethyl)-2, 8, 14, 20- tetraundecylcalix [4] resorcinarene-4, 6, 10, 12, 16, 18, 22, 24-octol, for predominant extraction of their ions from the ternary mixture of aqueous solution at different pH in a water layer. The hosting of Pb (II) by the diethylaminomethyl-calix [4] resorcinarene occurred efficiently at pH 6–7. The hosting of Pb (II), Cu (II), and Ni (II) ions for the ternary aqueous mixture was applied to the Langmuir isotherm. Adsorption was studied using nuclear magnetic resonance spectroscopy in a water–deuterium chloroform extraction system. Results showed that as the heavy metal ions were included into the host cavity, the observation of shifted peaks of water molecules from downfield to higher field was visible in the nuclear magnetic resonance spectra, meaning that water molecules were included with heavy metal ion into the host cavity. The spectra also showed that the diethylamino group expressed formation of the coordination complex between the diethylaminomethyl-calix [4] resorcinarene and Pb (II) for the purpose of predominant hosting of Pb (II).

A new organic/inorganic composite based on polyacrylonitrile and stannic molybdophosphate (PAN-SMP) as an adsorbent was synthesized under various conditions. The physico-chemical properties of this material were specified by elemental analysis, scanning electron microscope, infrared spectroscopy, and thermogravimetry studies. The synthesized material was found to be stable in demineralized water, dilute acids, under gamma radiation up to the total radiated of 100 kGy doses and in high temperature up to 500oC. Ion exchange capacity of the synthesized composite and its distribution coefficient (Kd) for several metal ions were determined. The results showed that PAN-SMP has a great affinity toward some metal ions such as, Tl+, Sr2+, Ba2+, UO22+ and La4+. Based on the determined Kd values, two binary quantitative separations of metal ions (Cr6+ from Cu2+ and Pb2+ from Cu2+) have been achieved on columns of this ion exchanger. The ability of PAN-SMP for decontamination of low-level liquid waste (LLLW) was also investigated.

Calcareous and smectitic clay samples from the Coniacian–Lower Campanian system, Tunisia, were used as adsorbents for the removal of copper and zinc from aqueous solutions in single and binary systems. Calcareous clay sample was treated with acetic acid to obtain carbonate-free sample that was also used for metals removal. The adsorption of metal ions onto natural clay was tested in a batch method by mixing 1 g/L of each sample with a metal ion solution of zinc (300 mmol/L) and/or copper 600 mmol/L under the operating pH of 6, and agitation speed of 200 rpm within the equilibrium time of 60 min at 25oC for single and binary systems. Our results showed that natural clay samples were mainly composed of silica, alumina, iron, and magnesium oxides. Adsorption data showed that the studied clay samples removed substantial amounts of heavy metals in single and mixed systems. Initial solution pH and carbonates contents enhanced the removal capacities of the studied clay samples, confirming their strong influencing effects. Thermodynamic parameters indicated an endothermic adsorption for metals removal by calcareous clay, but exothermic process for the smectitic sample. These results suggest that the Late Cretaceous clays, Tunisia, can be effectively used as natural adsorbents for the removal of toxic heavy metals in aqueous systems.

Metal-complex dyes are widely used in textile industry, but harmful to the environment and human health due to aromatic structure and heavy metal ions. The objective of this work was to evaluate the adsorption potential of bamboo biochar for the removal of metal-complex dye acid black 172 from solutions. Freundlich model was more suitable for the adsorption process of bamboo biochar than Langmuir isotherm, indicating multilayer adsorption of acid black 172 on a heterogeneous bamboo biochar surface. Adsorption kinetics analysis of pseudo-second-order and Weber–Morris models revealed that intraparticle transport was not the only rate-limiting step. The bamboo biochar exhibited a good adsorption performance even at high ionic strength. Analysis based on the artificial neural network indicated that the temperature with a relative importance of 29% appeared to be the most influential parameter in the adsorption process for dye removal, followed by time, ionic strength, pH and dye concentration.

In the present study, adsorption of lead (II) ions from aqueous solution by alluvial soil of Bhagirathi River was investigated under batch mode. The influence of solution pH, sorbent dose, initial lead (II) concentration, contact time, stirring rate and temperature on the removal process were investigated. The lead adsorption was favored with maximum adsorption at pH 6.0. Sorption equilibrium time was observed in 60 min. The equilibrium adsorption data were analyzed by the Freundlich, Langmuir, Dubinin–Radushkevich and Temkin adsorption isotherm models. The kinetics of lead (II) ion was discussed by pseudo first-order, pseudo second-order, intra-particle diffusion, and surface mass transfer models. It was shown that the adsorption of lead ions could be described by the pseudo second-order kinetic model. The activation energy of the adsorption process (E a) was found to be -38.33 kJ mol-1 using the Arrhenius equation, indicating exothermic nature of lead adsorption onto alluvial soil. Thermodynamic parameters, such as Gibbs free energy (DG 0), the enthalpy (DH 0), and the entropy change of sorption (DS 0) have also been evaluated and it has been found that the adsorption process was spontaneous, feasible, and exothermic in nature. The results indicated that alluvial soil of Bhagirathi River can be used as an effective and low cost adsorbent to remove lead ions from aqueous solutions.

In this study, palm shell activated carbon modified with task-specific ionic liquid was used as a novel electrode component for the potentiometric determination of cadmium ions in water samples. The proposed potentiometric sensor has good operating characteristics, including relatively high selectivity towards the Cd (II) ion, a Nernstian response to Cd (II) ions in a working concentration range of 1.0×10-9-1.0×10-2 M, with a reasonable detection limit of 1×10-10 M and a slope of 30.90±1.0 mV/decade. No significant changes in electrode potential were observed when the pH was varied over the range of 4-9. A direct technique based on the use of ion-selective electrode potentiometry has been developed in our laboratory for the study of reaction kinetics and kinetic methods of analysis by continuous monitoring of the rate of production or consumption of an ion. The apparent adsorption rate constant was estimated assuming pseudo-second-order kinetics. Additionally, the proposed electrode has been successfully used for the determination of the cadmium content in real samples without a significant interaction from other cationic or anionic species.

Eight different low cost starchy agroresidues namely Barley (B), Wheat bran (WB), Sattu (S), Rice powder (RP), Corn flour (CF), Rice husk (RH), Yellow peas split (YPS) and arrowroot (A) were used for solid culturing of Bacillus subtilis DJ5 for production of novel hyperthermostable B amylase. Various process parameters like initial moisture content, inoculum load, medium pH and incubation temperature affecting enzyme production were optimized to ensure maximum enzyme yield. Only 10% inoculums load and medium pH of 6.9 was found sufficient to achieve maximum enzyme production in all substrates in a decreasing order, B>WB>S>RP>CF>RH>YPS>A. Optimum b amylase production was highly dependent on initial moisture content of substrate as observed from varying requirement of moisture for different substrates. Only 50% moisture was sufficient for maximum enzyme production of 84.29 U/gdm in CF. For B, RH, YPS, and A 60% initial moisture resulted in higher production of 120.34, 35.19, 26.59, and 21.58 U/gdm, respectively, at 37oC. However, for S and RP higher (70%) moisture content allowed 113.4 and 85.56 U/gdm enzyme production, respectively. Under optimized conditions, maximum B amylase production was observed after 25 h for A, YPS, RH, RP; 41 h for B, WB, CF, and 45 h for S.

Using a portable emissions measurement system, 16 gasoline passenger cars were tested on a fixed route consisting of different types of roads in Macao and the data were normalized with the vehicle-specific power bin method. The normalized HC, CO and NO X emission levels of the seven passenger car samples with model year older than 2000 were 3.19±5.04, 14.59±22.88, 2.57±2.12 g/km, respectively. The HC, CO and NO X emission levels of other newer samples were 0.02±0.02, 0.23±0.29 and 0.10±0.13 g/km, respectively. The scrappage of old passenger cars in Macao should be a high priority to control the total emissions of motor vehicles. Based on relative emission levels, a clear and similar pattern for gaseous pollutants and fuel consumption with driving conditions was identified. The emissions of HC, CO and NO X are best fitted to average speed with inverse functions. Fuel consumption is best fitted to average speed with a power function. Compared to the average driving conditions, the emission factors of HC, CO and NO X and fuel consumption of gasoline passenger cars during the rush hours on the Macau Peninsula will be increased by 61, 55, 45 and 90%, respectively. This situation will deteriorate by 2015 if no further transportation management strategies are implemented in Macao. To save energy and mitigate the air pollutant emissions in the urban area, improved traffic planning and travel demand management are also necessary.

Methoxychlor is an organochlorine pesticide used worldwide against several insect pests, resulting in human exposure. This pesticide mimics endocrine hormone functions, interfering with normal endocrine activity in humans and wildlife. For this reason, it is imperative to develop methods to remove this pesticide from the environment, and though, bioremediation using microorganisms results as an excellent strategy. Five Streptomyces spp. strains previously isolated from organochlorine-polluted sites and capable to grow and remove methoxychlor were combined as different mixed cultures to increase methoxychlor removal. From the 39 consortia tested, one consortium (Streptomyces spp. A6, A12, A14, M7) was selected because of its high pesticide removal and specific dechlorinase activity to be assayed on slurry and soil systems. This consortium showed higher biomass values (8.3×106±5.7×05 CFU mL-1) and methoxychlor removal (56.2±2.3%) on enriched slurry than in non-enriched slurry (7.3×105±1.2×105 CFU mL-1 and 45.6±7.4% of pesticide removal). In soil systems, Streptomyces consortium showed higher growth (1.0×1011±5.0×1010 CFU g-1) than in enriched slurry, although differences in methoxychlor removal between both culture conditions were not statistically significant. Therefore, the selected Streptomyces consortium may be suitable for the development of in situ (soil) and ex situ (slurry bioreactor) bioremediation methods because of their potential to remove methoxychlor from different systems.

The importance of mitigation of climate change due to greenhouse gas (GHG) emissions from various developmental and infrastructure projects have generated interest at global level to reduce environmental impacts. Life Cycle Assessment (LCA) may be used as a tool to assess GHG emissions and subsequent environmental impacts resulting from electricity generation from thermal power plants. This study uses life cycle approach for assessing GHG emissions and their impacts due to natural gas combined cycle (NGCC) and imported coal thermal power plants using the IPCC 2001 and Eco-Indicator 99(H) methods in India for the first time. The total GHG emission from the NGCC thermal power plant was 584 g CO2 eq/kWh electricity generation, whereas in case of imported coal, it was 1127 g CO2 eq/kWh electricity generation. This shows that imported coal has nearly ~2 times more impacts as compared to natural gas in terms of global warming potential (GWP) and human health as Disability Adjusted Life Years (DALY) from climate change due to GHG emissions such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O).

During two last decades, numerous technologies and approaches are presented for treating contaminants in liquids and solutions. Among them, thermal plasma has shown rapid kinetic and high destruction efficiencies due to very high temperature and highly active radicals. Hence, the use of thermal plasma for treatment of the contaminants in liquids and solutions has received a lot of attention in view of its low environmental impacts. This review focuses on thermal plasma, and it describes the current status of liquid and solution treatment using this technology. A comprehensive analysis of the available scientific and technical literature on liquid and solution plasma treatment is presented, including the treatment of a variety of contaminants in liquids and solutions via different kinds of thermal plasma. The principles of thermal plasma generation and the available plasma technologies with potential applications to generate valuable products from liquid waste are presented. In addition, the results of the thermal plasma processes for the treatment of specific contaminants are investigated. In light of the investigated literature, thermal plasma is found to have a significant potential to treat the liquid wastes.