Water environment

About: Water environment is a research topic. Over the lifetime, 13384 publications have been published within this topic receiving 125138 citations.

Preparation of Size-Controlled TiO2 Nanoparticles and Derivation of Optically Transparent Photocatalytic Films

Abstract: TiO2 nanoparticles were prepared by hydrothermal reaction of titanium alkoxide stabilized in acidic ethanol/water solution. The sizes of particles have been controlled to the range of 7−25 nm by adjusting the concentration of Ti precursor and the composition of the solvent system. The TiO2 samples synthesized under this acidic ethanol/water environment were mainly primary particles in anatase phase without secondary structure. The suspension of as-prepared 7-nm-sized TiO2 nanoparticles demonstrates long-term stability, and has been applied successfully for the fabrication of ultra-transparent particulate TiO2 films. The photocatalytic efficiency of TiO2 films prepared from the 7-nm-sized nanoparticles was 1.6 times of that of films derived from Degussa P25 in decomposing gaseous 2-propanol.

Advances in heterogeneous photocatalytic degradation of phenols and dyes in wastewater : a review

Abstract: The heterogeneous photocatalytic water purification process has gained wide attention due to its effectiveness in degrading and mineralizing the recalcitrant organic compounds as well as the possibility of utilizing the solar UV and visible light spectrum. This paper aims to review and summarize the recently published works in the field of photocatalytic oxidation of toxic organic compounds such as phenols and dyes, predominant in waste water effluent. In this review, the effects of various operating parameters on the photocatalytic degradation of phenols and dyes are presented. Recent findings suggested that different parameters, such as type of photocatalyst and composition, light intensity, initial substrate concentration, amount of catalyst, pH of the reaction medium, ionic components in water, solvent types, oxidizing agents/electron acceptors, mode of catalyst application, and calcinations temperature can play an important role on the photocatlytic degradation of organic compounds in water environment. Extensive research has focused on the enhancement of photocatalysis by modification of TiO2 employing metal, non-metal and ion doping. Recent advances in TiO2 photocatalysis for the degradation of various phenols and dyes are also highlighted in this review.

Ecological mechanisms underlying the sustainability of the agricultural heritage rice–fish coculture system

Abstract: For centuries, traditional agricultural systems have contributed to food and livelihood security throughout the world Recognizing the ecological legacy in the traditional agricultural systems may help us develop novel sustainable agriculture We examine how rice–fish coculture (RF), which has been designated a “globally important agricultural heritage system,” has been maintained for over 1,200 y in south China A field survey demonstrated that although rice yield and rice-yield stability are similar in RF and rice monoculture (RM), RF requires 68% less pesticide and 24% less chemical fertilizer than RM A field experiment confirmed this result We documented that a mutually beneficial relationship between rice and fish develops in RF: Fish reduce rice pests and rice favors fish by moderating the water environment This positive relationship between rice and fish reduces the need for pesticides in RF Our results also indicate a complementary use of nitrogen (N) between rice and fish in RF, resulting in low N fertilizer application and low N release into the environment These findings provide unique insights into how positive interactions and complementary use of resource between species generate emergent ecosystem properties and how modern agricultural systems might be improved by exploiting synergies between species