Evaluation of the photocatalytic degradation mechanism of methylene blue using nascent and Ag+ ions-modified TiO2

In photocatalytic removal of organic pollutants, adsorption and degradation are two important processes that take place. Various instrumental techniques and trapping experiments have been used to identify the reactive species and the mechanism of photodegradation. The present work focuses on investigating the mechanism of photo-induced degradation from the comparative characterization of fresh and used samples, isotherm models, competitive adsorption, and desorption studies of pure and Ag+-modified TiO2 NPs. The comparative characterizations of fresh and used NPs were carried out with FT-IR, EDX, and XRF analyses after methylene blue (MB) degradation. The Ag+ doped TiO2 used in this study was fabricated using simple impregnation technique. The prepared NPs were characterized using techniques including XPS, XRD, SEM/EDX, XRF, UV-DRS, and pH point-zero charge analyses (pHPZC). The Ag+-modified TiO2 NPs showed improved efficiency compared to pure TiO2 NPs using normal compact fluorescent light (CFL). The Langmuir and Freundlich isotherm models were applied to test the adsorption behavior on the surface photocatalysts. The investigational data finest fitted to the Langmuir isotherms model compared to Freundlich model, suggesting the homogeneous monolayer adsorption followed by degradations. The competitive removal of MB in the presence of a photo-generated electrons trapper (Cd2+) was enhanced almost 3-folds (115 mg/L) compared to the removal from a single MB solution (40 mg/L). The characterization of the used samples as well as adsorption in the dark and negligible desorption of used samples support the involvement of the proposed photo-induced degradation mechanism.

Estimation and Quantification of Toxic Metals in Hugely Consumed Chicken Livers by Advanced Diagnostic Approaches

Contamination of toxins in chicken's liver is a serious concern for human health owing to related threats of cytotoxicity and general pathologies after their digestion. The quantitative investigations were accomplished by calibration curves plotted for all the detected toxins via typical samples arranged in the known concentrations in the chicken liver's matrix. The chicken liver samples were collected from the Khyber Pakhtunkhwa province of Pakistan and found to contain heavy metals like Cu, Mn, Ni, Pb, and Zn. The analytical estimations were performed under the suppositions of local thermodynamic equilibrium (LTE) in terms of optical thin plasma. The maximum concentrations (parts per million) of Cu, Mn, Ni, Pb, and Zn were as 2.87 ± 0.02 ppm, 7.80 ± 0.13 ppm, 2.84 ± 0.02 ppm, 4.00 ± 0.08, and 83.5 ± 2.10 ppm respectively. Abundance of Cu, and Pb was found considerably beyond the maximum accepted boundary of WHO. Likewise, the level of Ni exceeded the permitted bounds of WHO in samples 01 and 02. To validate our laser-induced breakdown spectroscopy investigation, we approximated the abundance of identical (duplicate) chicken livers through digesting the specimens in suitable solvents by a typical technique such as inductively coupled plasma/optical emission spectrometry (ICP/OES) and the results acquired were in outstanding harmony. Furthermore, the existence of detected toxins was also checked using energy dispersive X-ray spectroscopy (EDX). It is worth stating that larger amounts of Cu, Ni, and Pb in poultry may cause a severe hazard to customers which required security actions and precautions. Our findings are extremely important to make an awareness among the people due to associated health hazards after the digestion of toxins through chicken liver and to protect numerous human lives.

An emerging photocatalyst for wastewater remediation: a mini-review on CaCu3Ti4O12 photocatalysis

Ceramics-based filter for water treatment is an ancient technology to procure potable water at the household level. The traditional clay pots (vessels or hollow cylindrical container) have been used since long in the developing countries. The ceramic material (CaCu₃Ti₄O₁₂ or CCTO) is a hetero-junction of titanium oxide, a well-known UV-active photocatalyst, and visible light absorbing CuO materials. This hetero-junction is able to overcome the limitations such as high bandgap, poor stability, low efficiency, and high photo-generated charge (e^-/h⁺) recombination rate, associated with the other commonly used metal oxide semiconductor photocatalysts. Moreover, the low-cost, viable and facile synthesis routes for CCTO triggered its potential applications in photoelectrochemical and photocatalytic processes. This review will elaborate on the available literature demonstrating the visible light activity of CCTO photocatalysts in water treatment technologies. Furthermore, the mechanism of photocatalysis and synthesis routes are presented in this work for broader impact of the CCTO potential applications. The extended porous character and excellent surface texture have made the ceramic materials as an ideal choice to combat the bacteria, pathogens and turbidity in aqueous medium at household level. Specifically, the controlled size and shape make the CaCu₃Ti₄O₁₂ (CCTO) an excellent visible light-driven photocatalyst, involving highly reactive species such as ^•OH, ^•O₂^- anions, h⁺, and e^-, for the removal of organic and inorganic pollutants from water.

An overview of polymeric nano-biocomposites as targeted and controlled-release devices

In recent years, controlled drug delivery has become an important area of research. Nano-biocomposites can fulfil the necessary requirements of a targeted drug delivery device. This review describes use of polymeric nano-biocomposites in controlled drug delivery devices. Selection of suitable biopolymer and methods of preparation are discussed.

A mini-review on rare earth metal-doped TiO2 for photocatalytic remediation of wastewater

Titanium dioxide (TiO2) has been considered a useful material for the treatment of wastewater due to its non-toxic character, chemical stability and excellent electrical and optical properties which contribute in its wide range of applications, particularly in environmental remediation technology. However, the wide band gap of TiO2 photocatalyst (anatase phase, 3.20 eV) limits its photocatalytic activity to the ultraviolet region of light. Besides that, the electron-hole pair recombination has been found to reduce the efficiency of the photocatalyst. To overcome these problems, tailoring of TiO2 surface with rare earth metals to improve its surface, optical and photocatalytic properties has been investigated by many researchers. The surface modifications with rare earth metals proved to enhance the efficiency of TiO2 photocatalyts by way of reducing the band gap by shifting the working wavelength to the visible region and inhibiting the anatase-to-rutile phase transformations. This review paper summarises the attempts on modification of TiO2 using rare earth metals describing their effect on the photocatalytic activities of the modified TiO2 photocatalyst.

Minimum induction dose (MID) of thiopentone in Pakistani patients

The thiopentone dose needed for abolition of eyelash reflex was studied in 505 Pakistani patients who were divided in three subgroups, i.e., age less than 16 years, between 16 and 60 years, and over 60 years. The minimum induction dose for thiopentone was then determined in the three groups and the effect of sex, ASA classification, premedication and advancing age were seen. The minimum induction dose in the adult patients (16-60) was 215.8 +/- 66 mgs (3.48 mgs/kg). Both the adult groups and the elderly showed a statistical difference in the dose required by the males and females, but this difference was not seen in children. Thiopentone dose also showed a steady decline as the age progressed. A statistical correlation existed between ASA I and II patients compared to ASA III who required less thiopentone. The premedicated patients required less thiopentone compared to those who did not receive a premedication. Our patients required a lesser dosage for abolition of eyelash reflex than the figures recommended for British population. We recommend a dose of 3.5 mg/kg for adult Pakistani males and 3.3 mg/kg for adult females.