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Among the aquatic pollutant remediation reactions, the reduction of toxic Cr(VI) to a benign Cr(III) is of significant interest. Among the avrious remediation methods, photocatalysis is considered optimal due to its efficiency and eco-friendly nature. Therefore, the development of highly active, visible-light-responsive, and noble-metal-free photocatalysts for the elimination of toxic heavy metal ions from wastewater is highly desirable. In this study, a facile two-step method, comprising solvothermal and hydrothermal, was used to synthesize visible-light-responsive CdS/MoS2 heterojunctions (CM-HJs). Extensive structural characterization was performed to assess the crystal structure (XRD and XPS), morphology (SEM and BET), and optical (UV-Vis) properties of the as-synthesized photocatalysts. Aquatic Cr(VI) photoreduction was conducted on these photocatalysts under visible light irradiation. The results revealed the high photocatalytic activity and photostability of CM-HJs for Cr(VI) reduction compared to the bare CdS. Among the heterojunctions, CM-10 (10 wt % MoS2) exhibted the highest acvtivty, reducing 99.04% of Cr(VI) within 60 min. The enhanced photocatalytic activity can be attributed to its high light harvesting capability and efficient separation and transportation of the produced electron-hole pairs due to the intimate contact interfaces and matching band potentials of CdS with MoS2. Based on the literature and experimental evidence, a photocatalytic mechanism for the photoreduction of Cr(VI) is discussed in detail. The effect of different parameters; like the amount of photocatalyst, amount of Cr(VI), and pH were also evaluated. Like other good photocatalysts, CM-10 owes good photostability and recyclability. [ABSTRACT FROM AUTHOR]

A one-step, facile and scalable hydrothermal route was employed to synthesize molybdenum disulfide (MoS2) nanoflowers (NFs) for use in the photodegradation of Congo red (CR) dye. The phase purity, morphology, and structural features of the produced mesoporous MoS2-NFs were examined using PXRD, FESEM, EDX, XPS, BET, Raman and UV-visible DRS techniques. The nitrogen adsorption-desorption isotherms display a clear H3-type of hysteresis loop at P/Po of 0.8–1.0, which affords an insight into the mesoporous nature of the MoS2 NFs with a pore diameter of 1.5 to 40 nm. The mesoporous MoS2 NFs showed excellent CR degradation activity under solar light irradiation with a Kapp of 0.76 × 10−2 min−1. Importantly, the results showed a notable impact of reaction media on the degradation of CR suggesting that pH 7 is a favorable medium for this particular catalytic reaction. A kinetic study has illustrated that photodegradation of CR follows pseudo-first order kinetics. This work illustrates that mesoporous MoS2 NFs can be used as an efficient photocatalyst for the degradation of highly toxic and hazardous organic dyes in environmental remediation. [ABSTRACT FROM AUTHOR]

Hexavalent chromium, Cr(VI), is a toxic, mutagenic and carcinogenic species. We report here the semiconductor-based, photocatalytic reduction of Cr(VI) to trivalent chromium, Cr(III), using CdS nanorods (NRs) as the photocatalyst under visible light illumination. The CdS NRs were synthesized by a facile and scalable solvothermal method in which ethylenediamine acts as solvent and morphology controller. The CdS NRs produced were studied by PXRD, Raman, FESEM, EDX, XPS, PL, UV-visible DRS and BET techniques in order to investigate their structural, morphological and optical properties, as well as their porosity. The photoreduction of Cr(VI) to Cr(III) under visible light illumination was performed under a variety of conditions, i.e., varying the irradiation time, pH, substrate concentration, and the amount of photocatalyst. The maximum photoreduction of Cr(VI) to Cr(III) (99%) was achieved using 60 min of irradiation under acidic conditions (pH 4). The excellent photoreduction ability of the CdS NRs can be attributed to their rod-like structure together with their small particle size, large surface area, and clean surfaces. These properties enhanced separation of the photo-generated electron-hole pairs, which was confirmed by the XRD, BET, and PL measurements. In addition, the results of a kinetic study indicated that the photoreduction of Cr(VI) to Cr(III) follows a pseudo-first-order kinetic model. A possible mechanism for the photocatalytic reduction of Cr(VI) to Cr(III) is also proposed in this paper. [ABSTRACT FROM AUTHOR]

The quality of wheat grain can impact the farmer's income and also affect human health. The interaction between the planting time and genetic information indicated a significant effect. Determining correct planting time that can exploit the result of interaction between genotypes and atmosphere that enhance the production and grain quality. The main objective of this study was to choose the more suitable planting dates that maximize the wheat production and quality of wheat grain in cotton-wheat cropping system at different locations. Four wheat cultivars were planted at November 10th, 20th, December 1st, and December 10th at three different cottonwheat system growing districts, i.e., Bahawalpur, Khanewal, and Multan during both years. Late sown crop December 10th recorded maximum protein content (16.32%), starch contents (55.24%), and gluten content (34.19%) while early sown crop showed maximum moisture content (23.33%). Cultivar ASS-2011 demonstrated maximum protein content (13.47%), moisture content (10.73%), and starch content (55.09% and gluten content (33.66%). Year-II recorded the maximum protein content 11.95% moisture content 13.91%, starch content (53.89%), and gluten content 4.90% as compared 1st year in case of wheat crop. Wheat cultivar AAS-2011 showed best results regarding quality attributes in case of the late sown condition. [ABSTRACT FROM AUTHOR]

The main objective of this research is to study the adsorption behaviour of malachite green and methylene blue dyes onto the surfactant modified natural clays. The results of SEM, XRD, IR, and thermal analysis confirms the intercalation of organic moiety in to the clay. The adsorption results show that pseudo-first order kinetics best fitted for both the dyes adsorbed on organo-clay. The data also reveals that both dyes are in a good agreement with Langmuir isotherm in both types of modified clays. The value of separation factor, RL, from Langmuir equation and Freundlich constant, n, give an indication of favourable adsorption. The maximum adsorption capacity qm based on Langmuir model was found to be 294-303 mg/g at 25 °C, is in good agreement with the experimental values. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanostructured CdS was prepared by a facile one-pot solvothermal route. • The photocatalysts show superior photocatalytic activities in photo-degradation of MB dye. • Increasing the aspect ratio of the photocatalyst boosts the photocatalytic performance. • Possible mechanism of photoexcitation process and photo-degradation was proposed. • The photo-degradation of MB followed pseudo-first order kinetics. The development of a scalable and facile method for the synthesis of visible light driven photocatalytic materials to degrade toxic organic dyes is highly challenging and essential. In this regards, cadmium sulfide (CdS) nanorods and nanowires with controlled aspect ratio, grain size, surface area, and bandgap were synthesized by a simple solvothermal method, and their photocatalytic performances were exploited for the photo-degradation of methylene blue (MB) under simulated solar light. Extensive structural characterizations to identify the origin of the activities were performed. The photocatalytic activity measurements showed that the degradation of MB was 94.41%, 97.24%, 97.88%, and 99.82% for CdS prepared by following four different synthesis routes and increasing trend showed a correlation with the nanostructure morphology changing from nanorod and nanowires with increasing aspect ratio. It has been found that CdS nanowires show more pronounced photocatalytic activity due to the efficient separation of photo-generated electron-hole pairs induced by increased the aspect ratio and higher active surface area. [ABSTRACT FROM AUTHOR]

Contamination of water with organic dyes is a major environmental concern as it causes serious life-threatening environmental problems. The present research was designed to evaluate the potential of three different natural inorganic clays (NICs) i.e., Pakistani bentonite clay (PB), bentonite purchased from Alfa Aesar (BT), and Turkish red mud (RM) for malachite green (MG) dye removal from an aqueous solution. Various analytical techniques, namely X-ray fluorescence spectrometry (XRF), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), Brunauer–Emmett–Teller surface area measurement (BET), and thermogravimetric analysis (TGA), were used to investigate the physicochemical properties of the NICs samples. The effect of adsorption operational parameters such as contact time, aqueous phase pH, dye concentration, and amount of NICs on the adsorption behavior of MG onto NICs samples were investigated under the batch adsorption system. The equilibrium and kinetic inspection reflected the best description of MG adsorption behavior by the Langmuir isotherm model and pseudo-first-order kinetic model, respectively. The results indicated that the adsorption was favorable at higher pH. The maximum adsorption capacities calculated by Langmuir isotherm for PB, BT, and RM were found to be 243.90 mg/g, 188.68 mg/g, and 172.41 mg/g, respectively. It can be concluded that natural inorganic clays with a higher surface area can be used as an effective adsorbent material to remove the MG dye from an aqueous solution. [ABSTRACT FROM AUTHOR]

A simple synthetic protocol devoid of toxic surfactants was applied for the synthesis of CdS nanosheets and nanorods by thermolyzing bis (4-benzylpiperadine-1-carbodithioate-κ 2 S, S′) cadmium(II) ( 1 ) and propane-1,3-diyl bis (piperidincarbamodithioate)cadmium(II) ( 2 ) using ethylenediamine (en) as a solvent. The as obtained products were characterized by TEM, PXRD, and UV–Visible spectroscopy. The nanosheets ( 1) and nanorods ( 2) were confirmed by HR-TEM with a lattice spacing of 0.33 nm which corresponds to the 002 plane of hexagonal CdS, observations in consonance with XRD. Based upon the band gap obtained from UV–Vis, 2.91 eV (nanosheets) and 2.65 eV (nanorods), these nanoparticles (NPs) were used as solar light driven photocatalyst for the conversion of p -nitrophenol to p- aminophenol. The nanorods (8 min) were found slightly more efficient than nanosheets (10 min), and the conversion efficiency of both remained above 92% even after 3rd cycle without any structural damage as revealed by the afterward PXRD. The better catalytic activity of both morphologies can be attributed to quantum size effect and good optical absorbance. [ABSTRACT FROM AUTHOR]