North Eastern Hill University

About: North Eastern Hill University is a education organization based out in Shillong, Meghalaya, India. It is known for research contribution in the topics: Population & Catalysis. The organization has 2318 authors who have published 4476 publications receiving 48894 citations.

TiO2 photocatalysis: progress from fundamentals to modification technology

Abstract: Heterogeneous photocatalysis is a promising method among advanced oxidation processes, which can be used for degradation of various organic pollutants in water and air. In heterogeneous photocatalysis, illumination of an oxide semiconductor, usually the anatage form of titanium dioxide, by UV radiation produces photo-excited electrons () and positively charged holes (). In the aqueous phase, the illuminated surface is extensively regarded as a producer of hydroxyl radicals (). These hydroxyl radicals, holes, and conduction-band electrons can degrade organic pollutants directly or indirectly. However, the massive recombination of these photo-generated charge carriers and large band gap of limits its overall photocatalytic efficiency. These limitations can be overcome by changing surface properties of titania by adding suitable electron scavengers in the reaction medium or by modifying its electronic band structure through strategies like metal ion/nonmetal atom doping, narrow band-gap semiconductor...

Composition and dynamics of epilithic algae in a forest stream at Shillong (India)

Abstract: The seasonal dynamics of epilithic algae in a third order pristine forest stream were analyzed over a period of 2 years. Stream water was slightly acidic and nutrient poor. Encrusting, filamentous flocs, and filaments were found. Algal standing crop was high (mean concentration of Chl a 16–43 mg m−2) in spring. Filamentous algae contributed most to standing crop. Diatoms made up over 85% by number of the epilithon. Blue-greens were abundant upstream, and chlorophytes downstream. This shift was ascribed to greater light availability downstream. The community was more diverse during spring. Water current was the most important variable regulating epilithon structure. Total phosphorus (TP), orthophosphate (O-POinf4su3–), silica (Si4+), nitrate (NOinf3su–) and conductance correlated negatively with flow rate. Green algae showed a positive correlation to phosphorus during low and stable flow. During rapid runoff, diatoms were the most resistant forms. Seasonal change in the epilithic community was mainly regulated by fluctuations in flow rate.