| Triclosan,(2,4,4′-trichloro-2′-hydroxydiphenyl ether; TCS) is a nonionic, broadspectrum antimicrobic agent. Because of its favourable safety profile, it has been incorporatedinto a variety of personal care products, including deodorant soaps and sticks, handwash, andalso mouthrinse and dentifrice for providing control of dental plaque and breath odour. Due tothe wide use of products containing TCS, incomplete degradation of TCS in sewage treatment,TCS and its transformation product namely methyl-TCS have been detected in variousenvironmental matrices including wastewaters, freshwater, seawater and sediments, and bioticsamples such as fish and human breast milk. Most importantly, TCS is toxic to some aquaticspecies such as algae, daphnia and fish.An in vivo study has showed that TCS has thecapacity to affect thyroid hormone homeostasis in rats.And a number of studies have revealedthat TCS blocks lipid biosynthesis by specifically inhibiting the enoyl–acyl carrier proteinreductase and may induce bacterial resistance development. Therefore, It is necessary that arapid and green method is required to removal of TCS in water.With a small particle size, big specific surface area, high reactivity, andenvironment-friendly features, Iron nanoparticles has been a hot spot to degrade chlorinatedcontaminants. However, due to reunion and oxidation easily of iron nanoparticles, ironnanoparticles would lose its high activity. Iron nanoparticles should be modified to improveits dispersion and stability.The main conclusions of this work are made as follows:1.Nickel with iron nanoparticles generated bimetallic nano-systems that enhances thedegradation rates of organic contaminants in water. And environment-friendlymontmorillonite was used to support iron-nickel nanoparticles. The specific surface area ofthe supported Fe-Ni nanoparticles (28.7m2/g) is larger than it of unsupported Fe-Ninanoparticles (2.2m2/g). The presence of montmorillonite apparently decreased the extent ofaggregation and the size of the Fe-Ni particles. The degradation experiment was conducted byusing series of montmorillonite nanoparticles and metal zero-valent paricles to deal withtriclosan. Iron nanoparticles with nickel are better than iron nanoparticles. 2. Silver with iron nanoparticles generated bimetallic nanosystems that primarily controlits passivation and enhances the degradation rates of aquatic contaminants. And the pHcontrols the competition between Fe corrosion and silver formation, making the systemself-regulated.3. Scanning Electron Microscopy (SEM) of nanocomposites showed the presence ofspherical particles having a size of20-100nm and revealed proper dispersion as well asintercalation of Fe/Ag in the clay matrix. The EDS analysis performed on the bimetallicFe/Ag particles resulted in a spectrum with distinct peaks for Fe indicating element. While theoxygen is lower than iron atomic ration, the zero-valent iron exists. These nanocomposites arecharacterized using Brunauer–Emmett–Teller (BET) showed that the presence ofmontmorillonite apparently decreased the extent of aggregation and the size of the ironparticles. Iron, silver and crystalline iron oxide were detected by X-ray diffraction (XRD)patterns. In the Fourier Transform Infrared spectrum, the Si-O stretching vibrations ofmontmorillonite will change as added Fe/Ag. Fe or Ag built with the-O to form a bond andinteracted with Si-O. |
PDF Full Text Request