Pyrolysis of virgin and waste polypropylene and its mixtures with waste polyethylene and polystyrene

A comparison of waste and virgin polypropylene (PP) plastics under slow pyrolysis conditions is presented. Moreover, mixtures of waste PP with wastes of polyethylene (PE) and polystyrene (PS) were pyrolyzed under the same operating conditions. Not only the impact of waste on degradation products but also impacts of the variations in the mixing ratio were investigated. The thermogravimetric weight loss curves and their derivatives of virgin and waste PP showed differences due to the impurities which are dirt and food residues. The liquid yield distribution concerning the aliphatic, mono-aromatic and poly-aromatic compounds varies as the ratio of PP waste increases in the waste plastic mixtures. In addition to this, the alkene/alkane ratio of gas products shows variations depending on the mixing ratio of wastes.     

Recyling of plastic wastes via pyrolysis

Pyrolysis for the simultaneous generation of oils and gases can be convenient to obtain hydrocarbons and even to recover crude petrochemicals or to generate energy from waste plastics. A Gray–King apparatus has been used to pyrolyze waste polyethylene (PE), polystyrene (PS), both separately and with different compositions. Thermogravimetric analysis of waste plastics indicated the critical temperatures, which should be effective for pyrolysis. The chosen heating rate was low in order to achieve higher liquid yields. The results showed that waste PS yielded higher liquid, and waste PE yielded higher gaseous products. The dominant liquid product of PS waste was styrene whereas for waste PE, prophenylbenzene was the dominant pyrolysis product.     

Phytoplankton as index of water quality with reference to industrial pollution

In this paper Shannon-Weaver (SI-3.58-4.07, SII-3.1-3.72, SIII-1.64-2.25, SIV-2.54-2.95 and SV-3.09-3.23) diversity index was applied to surface phytoplankton to study the water quality status of river Bhadra receiving Mysore paper mill and Iron and steel mill effluent. A total of 45 species of phytoplankton belonging to 5 classes were recorded and study indicated that the phytoplankton diversity (Chlorophyceae-19 species, Bacillanophyceae-16 species, Cyanophyceae-07 species, Euglenophyceae-2 species and Chrysophyceae-1 species) did not reveal the same type of water quality (water temperature 24.62-27.32 degrees C, pH-7.08-7.25, electrical conductivity-67.49-201.94 micromhos/cm, dissolved oxygen-4.13-5.98 mgl(-1), chloride-12.30-40.85 mgl(-1), calcium-6.49-23.74 mgl(-1), total hardness 28.98-76.65 mgl(1), magnesium-4.69-15.92 mgl(-1), total alkalinity-77.26-86.53 mgl(-1), BOD-1.88-4.01 mgl(-1), COD - 16.53-45 mgl(-1), phosphate-0.001-0.53 mgl(-1), sodium-2.70-7.46 mgl(-1) and potassium-2.37-7.88 mgl(-1)). The investigation emphasized the need of phytoplankton community as index of water quality polluted by industrial effluents at the downstream stretch of the Bhadra river.     

Hepatoprotective activity of 1-(4-(Dimethylamino)Benzylidene)-5-(2-Oxoindolin-3-ylidene) Thiocarbohydrazone in rats

The aim of the present study was to evaluate the hepatoprotective activity of 1-(4-(dimethylamino)benzylidene)-5-(2-oxoindolin-3-ylidene) thiocarbohydrazone, a novel isatin derivative against carbon tetrachloride (CCl₄)-induced hepatotoxicity in rats. Hepatic damage was induced by administration of CCl₄ (1 ml/kg, b.w., p.o.) in combination with liquid paraffin (1:1) as a single dose. The hepatotoxic rats were treated with test compound at doses of 50 or 100 mg/kg for three days and liver damage biomarkers, including activities of serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT), serum alkaline phosphatase (ALP), and levels of total serum bilirubin (TB) measured in blood samples. Results demonstrated that treatment with test compound at doses of 50 or 100 mg/kg to hepatotoxic rats produced a significant dose-dependent reduction of elevated SGOT, SGPT, ALP activities and TB levels indicating a hepatoprotective effect that was confirmed by histopathological examination of liver tissues. The study results confirmed the hepatoprotective activity of 1-(4-(dimethylamino)benzylidene)-5-(2-oxoindolin-3-ylidene) thiocarbohydrazone in rats.     

Synthesis,characterization, and antimicrobial and antioxidant activities of novel bis-isatin carbohydrazone derivatives

In the present study, the synthesis of new bis-isatin carbohydrazone derivatives and their antimicrobial and antioxidant activities were investigated. The structures of new compounds were elucidated by Fourier transform infrared, ¹H nuclear magnetic resonance and mass spectra. The antimicrobial activity of the compounds was determined by using the two-fold serial dilution technique against various bacterial and fungal species in comparison to standard drugs. All synthesized compounds displayed a broad spectrum of activities with minimum inhibitory concentration values ranging from 6.25 to 100 μg/ml against tested microorganisms. The in vitro antioxidant activity was evaluated using 1,1-diphenyl-2-picryl-hydrazyl and hydrogen peroxide (H₂O₂), and the total antioxidant capacity by a phosphomolybdenum assay and their ability to chelate ferrous iron. In general, the derivatives were found to exhibit antioxidant activity. Further, the compounds with electron-withdrawing groups at the C5 position demonstrated significant antimicrobial and antioxidant activities.     

High-altitude and long-range transport of aerosols causing regional severe haze during extreme dust storms explains why afforestation does not prevent storms

Environmental Chemistry Letters - Climate change is predicted to induce more extreme events such as storms, heat waves, drought and floods. Dust storms are frequently occurring in northern China....     

Unravelling the turbulent structures of temperature variations during a gust front event: a case study

Environmental Fluid Mechanics - The simultaneous observations from a Doppler weather radar and an instrumented micrometeorological tower, offer an opportunity to dissect the effects of a gust front...     

Severity of zinc and iron malnutrition linked to low intake through a staple crop: a case study in east-central Pakistan

Environmental Geochemistry and Health - Micronutrients deficiency in soil–plant and human is well-addressed; however, little is known about their spatial distribution, magnitude of deficiency...     

Metallic wastewater treatment by sulfate reduction using anaerobic rotating biological contactor reactor under high metal loading conditions

An-RBC reactor is highly suited to treat metallic wastewater. Metal removal is due to sulfide precipitation via sulfate reduction by SRB. Cu(II) removal was the best among the different heavy metals. Maximum metal removal is achieved at low metal loading condition. Metal removal matched well with the solubility product values of respective metal sulfide salts. This study was aimed at investigating the performance of anaerobic rotating biological contactor reactor treating synthetic wastewater containing a mixture of heavy metals under sulfate reducing condition. Statistically valid factorial design of experiments was carried out to understand the dynamics of metal removal using this bioreactor system. Copper removal was maximum (>98%), followed by other heavy metals at their respective low inlet concentrations. Metal loading rates less than 3.7 mg/L?h in case of Cu(II); less than 1.69 mg/L?h for Ni(II), Pb(II), Zn(II), Fe(III) and Cd(II) are favorable to the performance of the An-RBC reactor. Removal efficiency of the heavy metals from mixture depended on the metal species and their inlet loading concentrations. Analysis of metal precipitates formed in the sulfidogenic bioreactor by field emission scanning electron microscopy along with energy dispersive X-ray spectroscopy (FESEM-EDX) confirmed metal sulfide precipitation by SRB. All these results clearly revealed that the attached growth biofilm bioreactor is well suited for heavy metal removal from complex mixture.