Effect of TiO2 nanoparticle on light fastness and degradation of dyedfabric with direct dye

The photocatalytic degradation of various dye solutions has been studied using nanoTiO2 (NTO) as a catalyst. The effect ofNTO on the light fastness of dyed cotton fabric has been studied using two different dyes, namely Direct Blue 71 and Direct Red 31with high and low light fastness respectively. After dyeing, the fabric is coated with NTO using a dip-pad–dry-cure process. Thecoated fabrics are then exposed to UV light for different periods of time. The results indicate that the coated cotton fabrics show asignificant photo-oxidative activity under UV light. The color change of cotton fabric dyed with Direct Blue 71 with high lightfastness is found less than that of the sample dyed with Direct red 31 with low light fastness

High selectivity for nitrogen in nitrate reduction on AgâZnO nanoparticles with formic acid as hole scavenger

A series of Ag-doped ZnO (AgâZnO) catalysts with a doping concentration up to 7wt% were prepared by a direct precipitation method. The prepared photocatalysts were characterized by XRD and TEM to determine their chemical composition and surface structure. The photocatalytic activity of different AgâZnO catalysts was evaluated in the photocatalytic reduction of nitrate in aqueous solution under UV illumination. In the experiments, formic acid was used as a hole scavenger to enhance the photocatalytic reduction reaction. The experimental results indicate that the presence of Ag in ZnO catalysts substantially enhances the photocatalytic reaction of nitrate reduction. It was found that the optimal dosage of 5wt%Ag in ZnO achieved the fastest reaction of nitrate reduction under the experimental condition. Nitrite ions were not monitored during the reaction and a negligible amount of ammonia formed. Hence selectivity to N2 is nearly 100%

Spectrophotometric determination of Naproxen as ion-pair with bromophenol blue in bulk, pharmaceutical preparation and human serum samples

A highly sensitive, accurate and simple spectrophotometric method was established for determination of naproxen (NAP). The method involved ion-pair complex formation between naproxen and bromophenol blue (BPB). The colored product was measured at 432 nm. The reaction conditions were optimized. The absorbance was found to increase linearly with increase in concentration of NAP which was corroborated by correlation coefficient value. Beer’s law was obeyed in the concentration range of 1-110 µg mL-1 with molar absorptivity of 9.756×103 L mol-1 cm-1. The limits of detection (LOD) and quantitation (LOQ) for the proposed method are 0.292 and 0.973 µg mL-1, respectively. Recovery of the method was carried out by standard addition method. Recovery studies and statistical data proved the accuracy, reproducibility and the precision of the proposed method. The common excipients did not interfere in this analysis. Hence the method is useful for routine estimation of naproxen in pharmaceutical formulation and human serum samples

Effect of TiO₂nanoparticle on light fastness and degradation of dyed fabric with direct dye

363-368The photocatalytic degradation of various dye solutions has been studied using nanoTiO2 (NTO) as a catalyst. The effect of NTO on the light fastness of dyed cotton fabric has been studied using two different dyes, namely Direct Blue 71 and Direct Red 31 with high and low light fastness respectively. After dyeing, the fabric is coated with NTO using a dip-pad–dry-cure process. The coated fabrics are then exposed to UV light for different periods of time. The results indicate that the coated cotton fabrics show a significant photo-oxidative activity under UV light. The color change of cotton fabric dyed with Direct Blue 71 with high light fastness is found less than that of the sample dyed with Direct red 31 with low light fastness