Titania (TiO 2 ) has been the focus of attention of researchers since the first demonstration of its capability to generate photocatalytic splitting of water into hydrogen and oxygen. However there seems to be a recent surge in the research activity involving modified TiO 2 nanoparticles (NP), which are considered to be more effective due to different physicochemical properties in comparison to unmodified fine particle analogs. Several strategies have been employed to modify titania to reduce recombination rates of photogenerated charge carriers to enhance optimal functioning of TiO 2 . Doping with cations and anions and coupling it with another semiconductor are the most well-known modification methods used. Titania nanocomposites are known to have a plethora of applications. Photoexcitation of these particles are seen to be extraordinarily effective in eliciting microbial death which makes it an attractive candidate for manufacturing of antimicrobial coatings. On the other hand, TiO 2 induces oxidation of various organic refractory compounds like tetracycline, sulfamethazine, and bisphenol. The photoelectrocatalytic oxidation technique which amalgamates the principle of photocatalysis and electrolysis serves as a newer, unswerving and cost effective water treatment process. In the biomedical arena, use is now acknowledged for photodynamic therapy of cancer, cell imaging, biological sensors, drug delivery system and as endonucleases. In the commercial front, it is utilized in creams owing to its small particle size which facilitates absorption through skin. It is also employed as UV blocking agents in sunscreen and commonly encountered as a brilliant white pigment in paint due to its brightness, high refractive index and resistance to discoloration.Its use in solar cells has also been reported. This review aims to encompass the new progress of modified TiO2 nanocomposites for efficient applications, emphasizing the future trends of TiO2 in arenas like healthcare, environment, biomedical, food, personal care and pharmacy and also highlights the commercial implications of this promising nanomaterial.
Background:Hexavalent chromium [Cr(VI)], a potential mutagen and carcinogen, is regularly introduced into the environment through diverse anthropogenic activities, including electroplating, leather tanning, and pigment manufacturing. Human exposure to this toxic metal ion not only causes potential human health hazards but also affects other life forms. The World Health Organization, the International Agency for Research on Cancer, and the Environmental Protection Agency have determined that Cr(VI) compounds are known human carcinogens. The Sukinda valley in Jajpur District, Orissa, is known for its deposit of chromite ore, producing nearly 98% of the chromite ore in India and one of the prime open cast chromite ore mines in the world (CES, Orissa Newsletter).Materials and Methods:Our investigation involved microbial remediation of Cr(VI) without producing any byproduct. Bacterial cultures tolerating high concentrations of Cr were isolated from the soil sample collected from the chromite-contaminated sites of Sukinda, and their bioaccumulation properties were investigated. Strains capable of growing at 250 mg/L Cr(VI) were considered as Cr resistant.Results:The experimental investigation showed the maximum specific Cr uptake at pH 7 and temperature 30°C. At about 50 mg/L initial Cr(VI) concentrations, uptake of the selected potential strain exceeded 98% within 12 h of incubation. The bacterial isolate was identified by 16S rRNA sequencing as Brevebacterium casei.Conclusion:Results indicated promising approach for microbial remediation of effluents containing elevated levels of Cr(VI).
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