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Nitrogen-doped titanium dioxide (N-TiO 2) nanoparticles were prepared using a modified sol-gel method. The as-prepared nanoparticles were characterized by state-of-the-art techniques for their optical, structural and morphological properties. The crystallite size, surface area and bandgap energy of reference TiO 2 and N-TiO 2 nanoparticles were found to be 16.1 and 10.9 nm, 83.6 and 131.8 m2 g−1 and 3.23 and 2.89 eV, respectively. The photocatalytic activities, in terms of 2,4-dichlorophenol (2,4-DCP) degradation, of reference TiO 2 and N-TiO 2 were found to be 46.9% and 65.4% at 120 min of treatments under UV light irradiation and 21.5% and 77.6% at 240 min of treatment under visible light irradiation, employing 153.4 µM 2,4-DCP, 1 g/L photocatalyst dosage, and pH 5.6. Interestingly, considerable H 2 production rate (i.e., 386 μmol h−1 g−1) was observed for visible/N-TiO 2 system in presence of 0.2 wt% Pt. The study revealed that visible/N-TiO 2 photocatalytic system can be used as an economically viable technology for environmental sustainability. [Display omitted] • Kinetic and mechanistic studies of 2,4-dichlorophenol were performed by visible/N-TiO 2 system. • 82.4% reduction in toxicity of 2,4-dichlorophenol solution was achieved by visible/N-TiO 2. • The rate of H 2 production was 386 μmol h−1 g−1 by using visible/0.2 wt% Pt/N-TiO 2 system. • Visible/N-TiO 2 is an economic and promising technology for environmental sustainability. • A waste to energy concept towards circular economy [ABSTRACT FROM AUTHOR]

Despite significant recent advancement in research, biogeochemical behavior of heavy metals with respect to their applied form is still topical. Moreover, metal toxicity to plants may vary with their stage of development/maturity. Therefore, this study for the first time evaluated the influence of ethylenediaminetetraacetic acid (EDTA) and citric acid (CA) on cadmium (Cd) accumulation and toxicity to germinating and young pea seedlings as well as in younger and older leaves. The experimental setup of current study consisted of two separate studies. The first study was performed on germinating seedlings grown in a Cd-contaminated sand media. Pea seeds were treated with two levels of Cd (Cd-25 and Cd-100) alone and combined with different levels of EDTA and CA. The second study was carried out in hydroponic solution. The influence of organic amendments on Cd accumulation and toxicity to pea plants was evaluated by determining Cd contents in pea seedlings, H 2 O 2 contents, chlorophyll contents and lipid peroxidation in younger and older leaves. Cadmium stress caused overproduction of H 2 O 2 in roots and leaves of pea seedlings. Cadmium-induced overproduction of H 2 O 2 caused a decrease in the pigment contents and increased lipid peroxidation. Application of EDTA at higher levels (81 and 200 µM) increased Cd accumulation by pea plants. However, CA did not affect Cd accumulation by pea. Both EDTA and CA increased Cd-induced H 2 O 2 production and lipid peroxidation. Younger pea leaves showed more sensitivity to Cd stress compared to older leaves. Similarly, Cd toxicity was more pronounced in germinating seedlings than young seedlings. Moreover, Pearson correlation and principal component analysis (PCA) showed very interesting correlations between treatments and stress responses of germination and young seedlings as well as younger and older leaves. Based on multivariate analysis, it is proposed that the Cd toxicity to pea plants greatly vary with its growth stage and the maturity of organs (younger or older leaves). [ABSTRACT FROM AUTHOR]

This study aimed to assess the concentrations of heavy metals such as cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in the available foodstuffs (crops, milk and water), their bioaccumulation in human body and potential human health risks in Swat valley, northern Pakistan. Heavy metal concentrations in foodstuffs and human blood (adults (18-above) and children (1–12 years)) were analyzed using atomic absorption spectrometer. The results revealed high level of Mn in foodstuffs followed by Cr>Cu>Zn>Ni>Cd>Pb, which significantly increased the levels of heavy metals in the adult׳s blood as compared to that of children in the order of Cr>Zn>Mn>Ni>Pb>Cu>Cd. Principal component analysis showed that selected foodstuffs were the possible sources of metal contamination in human blood, while correlation analysis revealed that the concentrations of Cr, Cu, Mn, Ni, Pb and Zn in foodstuffs significantly correlated with that in human blood. Moreover, risk assessments for individual metals via foodstuffs were found within safe limits, except for Cd (HQ>1); Whereas, for aggregate multiple metals the risk was calculated as 3.97E+00 (HI>1), in which water and milk were perceived as the greater contributors (81 percent) to HI; while fruits, grains and vegetables contributed 5 percent each, and pulses 4 percent. [ABSTRACT FROM AUTHOR]

Extensive research has been conducted on controlling carbon dioxide (CO 2), sulfur oxides (SO x), and nitrogen oxides (NO x) emissions in recent years with increasing environmental awareness. The primary contributor to climate change is the exponentially growing anthropogenic CO 2 , NO x, and SO x in the air from various energy and industrial sectors. Hence, several pre-combustion and post-combustion processes to mitigate these gases have been introduced and implemented. Despite the benefits of CO 2 , SO x , and NO x abatement technologies, researchers still have major challenges to deal with. While the removal efficiencies, operational costs, and resulting byproducts of conventional removal technologies are being improved, new technologies are also emerging. As it is evident from the current abundant reserves of coal that it will continue to be in a significant position among the principal sources of energy for more than a decade, the research for the reduction of CO 2 , NO x, and SO x is inevitable to save future generations from the harmful impacts of these pollutants. This review paper summarizes the progress of different emission control technologies at the plant level and introduces emerging technologies that are environment friendly. [Display omitted] • NO x , SO x and CO 2 emissions from fuel combustion and industries are of significant concern. • Several pre and post combustion processes have been devised to control emissions. • Adsorption, absorption, and membrane technologies for CO 2 capture have been promising. • For NOx reduction, SNCR process has relatively low capital and operational cost. • WFGD technology is the most extensively utilized process for SOx control. [ABSTRACT FROM AUTHOR]