Synthesis and investigation on synergetic effect of activated carbon loaded silver nanoparticles with enhanced photocatalytic and antibacterial activities

In this study, we synthesized silver nanoparticle-loaded cashew nut shell activated carbon (Ag/CNSAC). The synthesized samples were characterized by XRD, XPS, SEM with EDS, FT-IR, and BET analysis. The XRD, XPS, and EDS data provided convincing proof that Ag loaded on CNSAC is formed. The energy dispersive spectrum analysis and X-ray diffraction pattern both supported the face-centered cubic and amorphous structures of Ag/CNSAC. The SEM micrographs showed the inner surface development of Ag NPs and many tiny pores in CNSAC. The photodegradation of methylene blue (MB) dye by the Ag/CNSAC photocatalyst was investigated. This effective degradation of MB dye by Ag/CNSAC is attributed to the cooperative action of Ag as a photocatalyst and CNSAC as a catalytic support and adsorbent. In tests with gram-positive and negative bacteria including Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the as-synthesized Ag/CNSAC showed outstanding antibacterial efficiency. Additionally, this study demonstrates a workable procedure for creating an affordable and efficient Ag/CNSAC for the photocatalytic eradication of organic contaminants.

Effect of metal doping and non-metal loading on light energy driven degradation of organic dye using ZnO nanocatalysts

Photocatalytic degradation of azo dyes is seen as a viable technique for addressing environmental and energy concerns simultaneously. Therefore, the primary requirement is the creation of a better catalyst with adequate product selectivity for removal efficiency under solar light. Herein, pure ZnO and Cu (0.10 M) doped cotton stalk activated carbons with ZnO (Cu-doped ZnO/CSAC) were produced, and these are labelled as CZ1, CZ2, CZ3, and CZ3/CSAC, respectively. The optoelectronic and photodegradation efficiencies were examined regarding the impact of doping and loading samples. The XRD patterns confirmed that the CZ3/CSAC sample exhibited a hexagonal wurtzite structure. The XPS survey confirmed that Cu ions were incorporated into the ZnO lattice in a Cu²⁺ oxidation state. The band gap value (CZ3/CSAC) was reduced (2.38 eV) compared to pure ZnO and CZ3. Moreover, PL and EIS analysis proved more efficient at separating photoinduced charged carriers for CZ3/CSAC than all other samples. The CZ3/CSAC sample showed improved photocatalytic degradation efficiency (93.09%) compared to the pure ZnO and CZ3 samples using brilliant green (BG) dye under sunlight irradiation.

Development of biohybrid Ag2CrO4/rGO based nanocomposites with stable flotation properties as enhanced Photocatalyst for sewage treatment and antibiotic-conjugated for antibacterial evaluation

The proposed research outlines a facile method to synthesize Silver Chromate/reduced graphene oxide nanocomposites (Ag₂CrO₄/rGO NCs) with a narrow dissemination size for the ecological treatment of hazardous organic dyes. The photodegradation performance toward the decontamination of model artificial methylene blue dye was assessed under solar light irradiation. The crystallinity, particle size, recombination of photogenerated charge carriers, energy gap and surface morphologies of synthesized nanocomposites were determined. The experiment objective is to use rGO nanocomposites to increase Ag₂CrO₄ photocatalytic efficiency in the solar spectrum. Tauc plots of ultraviolet-visible (UV-vis) spectrum were used to calculate the optical bandgap energy of the produced nanocomposites ~1.52 eV, which resulted in a good photodegradation percentage of ~92 % after 60 min irradiation of Solar light. At the same time, pure Ag₂CrO₄ and rGO nanomaterials showed ~46 % and ~ 30 %, respectively. The ideal circumstances were discovered by investigating the effects of several parameters, including catalyst loading and different pH levels, on the degradation of dyes. However, the final composites maintain their ability to degrade for up to five cycles. According to the investigations, Ag₂CrO₄/rGO NCs are an effective photocatalyst and can be used as the ideal material to prevent water pollution. Furthermore, antibacterial efficacy for the hydrothermally synthesized nanocomposite was tested against gram-positive (+ve) bacteria viz. Staphylococcus aureus and gram-negative (-ve) bacteria viz. Escherichia coli. The maximum zone of inhibition for S. aureus and E. coli were 18.5 and 17 mm, respectively.

Adsorption of brilliant green dye onto activated carbon prepared from cashew nut shell by KOH activation: Studies on equilibrium isotherm

Activated carbon from cashew nut shell via a potassium hydroxide (KOH) at 600 °C in an N₂ atmosphere and their characteristics using FT-IR, XRD, SEM with EDS, and BET analysis was investigated. The cashew nut shell activated carbon obtained by KOH activation with a CNS/KOH ratio of 1:1 at 600 °C (N₂ atmosphere) for 2 h had the highest surface area (407.80 m²/g) as compared to other ratio samples. Amongst, CNS/KOH ratios of 1:1 sample are used for the adsorbent, they are effects of contact time, pH, adsorbent dose, and initial dye concentration on brilliant green (BG) removal efficiency were studied. Moreover, the Langmuir and Freundlich adsorption models consisted utilized to affirm the adsorption isotherms. They are, best fitting for BG experimental equilibrium data was achieved with the Langmuir isotherm, giving a maximum BG adsorption capacity of 243.90 mg/g.

Enhanced photocatalytic degradation of organic pollutants by Ag-TiO2 loaded cassava stem activated carbon under sunlight irradiation

Ag-doped TiO₂ and Ag-doped TiO₂ loaded cassava stem activated carbon (Ag: TiO₂/CSAC) were prepared by sol-gel method and are labelled as AT and AT/CSAC respectively. XRD results confirmed that the anatase-TiO₂ and crystalline size are decreased (12.37 nm) through the silver doping and cassava stem activated carbon loading. UV-Vis showed that the AT/CSAC makes a red shift from the absorption edge compared to pure and AT samples and then the band gap is reduced (2.81 eV). The increased surface area (238.51 m²/g) of the AT/CSAC sample through the Ag and CSAC, respectively. The consequences point out that the highest photodegradation efficiency (98.08%) of the TiO₂ upon silver doping and cassava stem activated carbon loading samples were brilliant green (BG) under sunlight irradiation.

Effect of doping and loading Parameters on photocatalytic degradation of brilliant green using Sn doped ZnO loaded CSAC

Sn doped ZnO loaded cotton stalk activated carbon (Sn-ZnO/CSAC) was prepared by chemical precipitation method, and the products were characterized. The XRD resultants confirm that the presence of hexagonal wurtzite phase of the bare ZnO. Furthermore, particular particle size gradually decreases (21.49 nm) due to doping and loading. UV-Vis absorption intensity of doped/loaded sample was red-shifted and then PL intensity is reduced. The photocatalytic performances of bare, Sn-doped ZnO and Sn-ZnO/CSAC was estimated by photodegradation of brilliant green (BG) under sunlight. The photodegradation of BG dye in 120 min over Sn-doped ZnO/CSAC is nearly 96.52%, which is considerably improved than bare ZnO (72.60%), respectively.

Enhanced sun light driven photocatalytic activity of Co doped SnO2 loaded corn cob activated carbon for methylene blue dye degradation

SnO₂ with different Co²⁺ doping concentrations and Co (0.075 M): SnO₂ loaded corn cob activated carbon (Co: SnO₂/CCAC) were prepared, and are labelled as CS1, CS2, CS3 and CS2/CCAC, respectively. The CS2/CCAC showed that the particle size (18.76 nm) and band gap (3.50 eV) are reduced with Co²⁺ doping and CCAC loading. Moreover, CS2/CCAC indicate that the decreased PL intensity and its lower value (2.156 kΩ) of impedance from EIS results which indicates the increased separation of the photogenerated e^-/h⁺ pairs. Thus, the result showed that CS2/CCAC maximum degradation efficiency of MB (95.38%) and the photocatalytic mechanism is also discussed.

Species Adulteration in the Herbal Trade: Causes, Consequences and Mitigation

The global economy of the international trade of herbal products has been increasing by 15% annually, with the raw material for most herbal products being sourced from South and Southeast Asian countries. In India, of the 8000 species of medicinal plants harvested from the wild, approximately 960 are in the active trade. With increasing international trade in herbal medicinal products, there is also increasing concern about the widespread adulteration and species admixtures in the raw herbal trade. The adverse consequences of such species adulteration on the health and safety of consumers have only recently begun to be recognised and documented. We provide a comprehensive review of the nature and magnitude of species adulteration in the raw herbal trade, and identify the underlying drivers that might lead to such adulteration. We also discuss the possible biological and chemical equivalence of species that are used as adulterants and substitutes, and the consequences thereof to consumer health and safety, and propose a framework for the development of a herbal trade authentication service that can help regulate the herbal trade market.

Synthesis and characterization of TiO2 loaded cashew nut shell activated carbon and photocatalytic activity on BG and MB dyes under sunlight radiation

Synthesis of titanium dioxide (TiO2) nanoparticles and TiO2 loaded cashew nut shell activated carbon (TiO2/CNSAC) had been undertaken using sol-gel method and their application in BG and MB dyes removal under sunlight radiation has been investigated. The synthesized photocatalysts were characterized by X-ray diffraction analysis (XRD), Fourier infra-red spectroscopy (FT-IR), UV-Vis-diffuse reflectance spectroscopy (DRS) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX). The various experimental parameters like amount of catalyst, contact time for efficient dyes degradation of BG and MB were concerned in this study. Activity measurements performed under solar irradiation has shown good results for the photodegradation of BG and MB in aqueous solution. It was concluded that the higher photocatalytic activity in TiO2/CNSAC was due to parameters like band-gap, number of hydroxyl groups, surface area and porosity of the catalyst. The kinetic data were also described by the pseudo-first-order and pseudo-second-order kinetic models.

A tiered barcode authentication tool to differentiate medicinal Cassia species in India

DNA barcoding is a desirable tool for medicinal product authentication. DNA barcoding is a method for species identification using short DNA sequences that are conserved within species, but variable between species. Unlike animals, there is no single universal DNA barcode locus for plants. Coding markers, matK and rbcL, and noncoding markers, trnH-psbA (chloroplast) and ITS2 (nuclear), have been reported to be suitable for the DNA barcoding of plants with varying degree of success. Sixty-four accessions from 20 species of the medicinal plant Cassia were collected, and analyzed for these 4 DNA barcoding markers. PCR amplification was 100% successful for all 4 markers, while intra-species divergence was 0 for all 4 Cassia species in which multiple accessions were studied. Assuming 1.0% divergence as the minimum requirement for discriminating 2 species, the 4 markers could only differentiate 15 to 65% of the species studied when used separately. Adding indels to the divergence increased the percentage of species discrimination by trnH-psbA to 90%. In 2-locus barcoding, while matK+rbcL (which is recommended by Consortium for the Barcoding of Life) discriminated 90% of the species, the other combinations of matK+ITS and rbcL+trnH-psbA showed 100% species discrimination. However, matK is plagued with primer issues. The combination of rbcL+trnH-psbA provided the most accurate (100% species ID) and efficient tiered DNA barcoding tool for the authentication of Cassia medicinal products.

Early experience of a CT coronary angiography service in a Scottish regional centre

Background

CT coronary angiography (CTCA) is an emerging diagnostic tool in the assessment of patients with suspected coronary artery disease. It has several advantages over conventional coronary angiography (CCA); however, its use is not yet widespread in large teaching centres.

Aims

To determine what proportion of patients who have CTCA, do not require subsequent CCA.

Methods

A prospective analysis of all patients referred for CTCA from the start of the service in January 2008 to April 2010.

Results

CTCA provided definitive diagnostic images in 85% of patients. Overall only 12% ( n = 33) of patients had subsequent CCA. The proportion of patients who subsequently had CCA reduced with time reflecting increasing confidence with the clinical service.

Conclusions

A CTCA service can be successfully established out with a large teaching centre hospital. Close working between cardiologists and radiologists leads to increased confidence in the service and obviates the need for CCA in a large proportion of patients.

Local knowledge and conservation of seagrasses in the Tamil Nadu state of India

Local knowledge systems are not considered in the conservation of fragile seagrass marine ecosystems. In fact, little is known about the utility of seagrasses in local coastal communities. This is intriguing given that some local communities rely on seagrasses to sustain their livelihoods and have relocated their villages to areas with a rich diversity and abundance of seagrasses. The purpose of this study is to assist in conservation efforts regarding seagrasses through identifying Traditional Ecological Knowledge (TEK) from local knowledge systems of seagrasses from 40 coastal communities along the eastern coast of India. We explore the assemblage of scientific and local traditional knowledge concerning the 1. classification of seagrasses (comparing scientific and traditional classification systems), 2. utility of seagrasses, 3. Traditional Ecological Knowledge (TEK) of seagrasses, and 4. current conservation efforts for seagrass ecosystems. Our results indicate that local knowledge systems consist of a complex classification of seagrass diversity that considers the role of seagrasses in the marine ecosystem. This fine-scaled ethno-classification gives rise to five times the number of taxa (10 species = 50 local ethnotaxa), each with a unique role in the ecosystem and utility within coastal communities, including the use of seagrasses for medicine (e.g., treatment of heart conditions, seasickness, etc.), food (nutritious seeds), fertilizer (nutrient rich biomass) and livestock feed (goats and sheep). Local communities are concerned about the loss of seagrass diversity and have considerable local knowledge that is valuable for conservation and restoration plans. This study serves as a case study example of the depth and breadth of local knowledge systems for a particular ecosystem that is in peril.

Mycorrhizal colonisation of three hybrid papayas (Carica papaya) under mulched and bare ground conditions

The use of straw mulching has been demonstrated to decrease soil loss and to improve soil moisture and soil organic matter content in conjunction with papaya (Carica papaya) cultivation. Mulching may also benefit soil biota. In this study, mulching was demonstrated to significantly (P < 0.05) improve arbuscular mycorrhizal fungal colonisation of papaya roots (by a factor of 2.4), but decreased spore density and species diversity (by a factor of 1.5), compared with cultivation in bare ground. The genera Glomus, Acaulospora, Gigaspora and Sclerocystis dominated in both mulched and bare ground systems. The increased mycorrhizal activity in the mulched treatments was matched by an increase in leaf phosphorus in 1995 but not in 1997.

DNA barcoding in land plants: evaluation of rbcL in a multigene tiered approach

DNA barcoding based on the mitochondrial cytochrome c oxidase 1 (cox1) sequence is being employed for diverse groups of animals with demonstrated success in species identification and new species discovery. Applying barcoding systems to land plants will be a more challenging task as plant genome substitution rates are considerably lower than those observed in animal mitochondria, suggesting that a much greater amount of sequence data from multiple loci will be required to barcode plants. In the absence of an obvious well-characterized plant locus that meets all the necessary criteria, a key first step will be identifying candidate regions with the most potential. To meet the challenges with land plants, we are proposing the adoption of a tiered approach wherein highly variable loci are nested under a core barcoding gene. Analysis of over 10 000 rbcL sequences from GenBank demonstrate that this locus could serve well as the core region, with sufficient variation to discriminate among species in approximately 85% of congeneric pair-wise comparisons. Use of a secondary locus can be implemented when required and can vary from group to group if necessary. The implementation of a barcoding tool has multiple academic and practical applications. It will speed routine identifications and the detection of alien species, advance ecological and taxonomic inquiry, permit fast and accurate forensic analysis of plant fragments, and can function as an additional layer of quality control in the food industry.