Simultaneous optimization of multiple performance characteristics in coagulation-flocculation process for Indian paper industry wastewater

The goal of this study was to optimize the coagulation-flocculation process in wastewater generated from the paper and pulp industry using a grey relational analysis (GRA)-based Taguchi method. Process parameters included types and doses of natural coagulants and coagulant aid, and pH. To track the efficiency of the treatment process, the following responses were chosen for optimization: chemical oxygen demand (COD), total dissolved solids (TDS) and turbidity of wastewater, alone or in combination or all together. Analysis of variance showed that the type and dose of the coagulant aid were the most significant parameters, followed by pH and the dose of the coagulant; the type of coagulant used was found to be insignificant in the coagulation-flocculation process. Optimization of process parameters to achieve lower turbidity and greater removal of COD and TDS was verified in a separate confirmatory experiment, which showed improvements in COD and TDS removal and a decrease in turbidity of 8.2, 6.35 and 26.17%, respectively, with the application of the Taguchi method and GRA.     

Study of n-ZnO/p-Si (100) thin film heterojunctions by pulsed laser deposition without buffer layer

ZnO/Si heterojunctions were fabricated by growing ZnO thin films on p-type Si (100) substrate by pulsed laser deposition without buffer layers. The crystallinity of the heterojunction was analyzed by high resolution X-ray diffraction and atomic force microscopy. The optical quality of the film was analyzed by room temperature (RT) photoluminescence measurements. The high intense band to band emission confirmed the high quality of the ZnO thin films on Si. The electrical properties of the junction were studied by temperature dependent current-voltage measurements and RT capacitance-voltage (C-V) analysis. The charge carrier concentration and the barrier height (BH) were calculated, to be 5.6 × 10¹⁹ cm^− 3 and 0.6 eV respectively from the C-V plot. The BH and ideality factor, calculated using the thermionic emission (TE) model, were found to be highly temperature dependent. We observed a much lower value in Richardson constant, 5.19 × 10^− 7 A/cm² K² than the theoretical value (32 A/cm² K²) for ZnO. This analysis revealed the existence of a Gaussian distribution (GD) with a standard deviation of σ² = 0.035 V. By implementing the GD to the TE, the values of BH and Richardson constant were obtained as 1.3 eV and 39.97 A/cm² K² respectively from the modified Richardson plot. The obtained Richardson constant value is close to the theoretical value for n-ZnO. These high quality heterojunctions can be used for solar cell applications.     

Effect of orally administered betel leaf (Piper betle Linn.) on digestive enzymes of pancreas and intestinal mucosa and on bile production in rats

The influence of two varieties of betel leaf (Piper betle Linn.) namely, the pungent Mysore and non-pungent Ambadi, was examined on digestive enzymes of pancreas and intestinal mucosa and on bile secretion in experimental rats. The betel leaves were administered orally at two doses which were either comparable to human consumption level or 5 times this. The results indicated that while these betel leaves do not influence bile secretion and composition, they have a significant stimulatory influence on pancreatic lipase activity. Besides, the Ambadi variety of betel leaf has a positive stimulatory influence on intestinal digestive enzymes, especially lipase, amylase and disaccharidases. A slight lowering in the activity of these intestinal enzymes was seen when Mysore variety of betel leaf was administered, and this variety also had a negative effect on pancreatic amylase. Further, both the betel leaf varieties have shown decreasing influence on pancreatic trypsin and chymotrypsin activities.     

Synthesis and characterization of TS-48, a titanium containing silica analog of ZSM-48

Crystalline titanium containing silica analog of ZSM-48 (TS-48) samples were synthesized using soluble peroxytitanate, fumed silica and diamino octane. All samples were characterized using a variety of techniques including XRD, IR, AAS, SEM, UV-Vis, XANES and catalytic testing in hydroxylation of phenol. Data suggest that titanium in these materials is linked to the framework. However, it was impossible to incorporate more than about 2 wt% Ti in the zeolite lattice. TS-48 samples prepared by this method had no activity for hydroxylation of phenol in the presence of hydrogen peroxide. The lack of activity of this material even though it showed all of the regular characteristics of other catalytically active titanium silicalites (i.e., TS-1 and TS-2) could be due either to diffusional limitations or to subtle differences in titanium environment.     

Voltammetric Method for Manganese Analysis in Indian Traditional Leafy Vegetables and Medicinal Plants Collected Around Tirupati Town, a Famous Pilgrim Center in India: The Catalytic Hydrogen Wave (CHW) Technique

Cost-effective, rapid, sensitive, and novel catalytic hydrogen wave technique (CHW) was developed for the analysis of manganese(II) in NH₄Cl–NH₄OH medium at pH 6.2 and produced catalytic hydrogen waves at −0.60 and −0.56 V Vs SCE with ammonium piperidine dithiocarbamate and ammonium morpholine dithiocarbamate, respectively, in various leafy vegetables and medicinal plants collected around Tirupati, Chittoor District, Andhra Pradesh which is one the famous pilgrim centers in India. Different optimal parameters like effect of pH, supporting electrolyte (NH₄Cl–NH₄OH) concentration, ligand and metal ion concentrations, and effect of adverse ions on peak height were studied to improve the sensitivity, selectivity, and detection limits CHW technique. This technique was compared in terms of Student t test and variance ratio f test with differential pulse polarography (DPP) method. The technique was applied for the analysis of manganese(II) in leafy vegetables and medicinal plants. The results obtained are in good agreement with DPP.