ABSTRACT
Dye removal from wastewater has received considerable attention with several classes of dye being investigated. Methylene blue has wide applications and can cause some harmful effects in humans. The use of clean technology of low-priced and biodegradable absorbents could be a good tool to minimize the environmental impact caused by dye manufacturing and textile effluents. The present study deals with the preparation of a novel sIPN [semi interpenetrating] hydrogel composed of copolymer of acrylamide and acrylicacid with poly vinyl alcohol as linear polymer there in. The adsorption abilities of hydrogels with different molar ratios for removal of methylene blue from aqueous solutions were investigated. A weighed quantity of dry hybrid hydrogel was immersed in 50 ppm MB solution and kept at 37 Degree C. The amount of MB adsorbed was measured spectrophotometrically [lambda= 661.6 nm] in periodically taken solution samples. The maximum dye adsorption concentration for hydrogel composites was 95% and no dye desorption of MB/polymer solutions was observed. Hence, the composites can be used as good membranes for removal of cationic dyes from aqueous solutions while they do not release harmful materials into water
Subject(s)
Coloring Agents , Wastewater , Adsorption , Polymers , Hydrogels , Acrylamide , Acrylates , Polyvinyl AlcoholABSTRACT
Two important disadvantages of amalgam restorations are lack of adhesion to tooth structure and marginal leakage. In recent studies, the use of dentin adhesive on cavity walls before the insertion of amalgam proved to be the best method to reduce microleakage and increase chemical adhesion. Fourty premolar and molar teeth were collected and divided into two groups. The class V cavities were made at the buccal surfaces of the teeth [Depth 1. 5 mm, Length 3 mm and Width 2 mm]. All the angles of cavo-surfaces were Buttjoint. The teeth were then washed, cleaned, dried and randomly divided into 2 groups, the first group was coated with 2 layers of varnish. The second group was coated with adhesive resin system and then restored with amalgam. The teeth were kept in distilled water for 24 hours. The prepared surfaces were then polished and thermocycling was performed. All prepared surfaces were coated with nail varnish up to 0.5 mm around the restorative material. Further more each group was randomly divided into 2 subgroups, one group was kept in distilled water for 24 hours and the other group for 5 months. All groups were afterwards kept in 0.5% basic fuchsin solution for 24 hours. The teeth were then mounted in Acrylic resin, were cut into two halves from the centre of preparation with a diamond saw and checked by a stereomicroscope for determining the microleakage rate. Comparison between two groups showed degree of dye penetration into margins of restorations with Rely X ARC was lower than that of varnish. However no significant differences were observed among the groups except for occlusal margins after 24 hours and 5 months