Microplastic contamination in Ashtamudi Lake, India: Insights from a Ramsar wetland.

Estuaries function as temporary storage sites for plastic debris, influencing the distribution of microplastics (MPs) across ecosystems. This research delves into the presence of MPs in the water, sediment, fish, and shellfish of Ashtamudi Lake, a Ramsar wetland with brackish water located on the southwest coast of India. Given the lake's significance in supporting the livelihoods of numerous fishers and acting as a vital source of fishery resources for both local consumption and export, examining the contamination of the system by MPs becomes particularly pertinent. The highest percentage composition of MPs was found in macrofauna at 60.6% (with fish at 19.6% and shellfish at 40.9%), followed by sediment (22.8%) and water (16.7%). The primary types of MPs identified in all samples were fibers (35.6%), fragments (33.3%), and films (28%), with beads being the least represented at 3.03%. ATR-FTIR and Raman spectra analysis identified five polymers from shellfish (polypropylene, polyethylene, polystyrene, nylon, and polyvinyl chloride), five from fish guts (nylon, polypropylene, polyethylene, polyurethane, and polysiloxane), four in sediment (polypropylene, polyethylene, nylon, rayon), and four in water samples (polypropylene, polyethylene, nylon, and polystyrene). SEM-EDAX analysis of MPs obtained from the samples revealed degradation and the presence of inorganic elements such as Na, Mg, Al, Si, S, K, Cl, P, and Ca, as well as heavy metals like Pb, Mo, Rh, Pd, Ti, and Fe. The existence of these plastic polymers and heavy metals in microplastic samples poses a threat to vulnerable biota; people consume contaminated fish and shellfish, underscoring the importance of monitoring MPs in lake water. This investigation of MPs in Ashtamudi Lake highlights the system's susceptibility to plastic pollution and the bioavailability of smaller MPs to aquatic organisms. Identified sources of MPs in the lake include fishing and aquaculture activities, sewage pollution, improper solid waste management in lake watersheds, and unsustainable tourism. Upstream and downstream management interventions are recommended to address MP pollution in Ashtamudi Lake.

Development and Elemental Analysis of a Novel Strontium-Doped Nano-Hydroxyapatite Paste and Evaluation of Its Remineralization Potential: An In Vitro Study.

Background Early detection and non-invasive methods to treat early caries lesions using new remineralizers are at the heart of today's caries management. The goal of the study is to develop a novel strontium-doped nano-hydroxyapatite paste, analyze its chemical composition, and evaluate the remineralization potential. Methodology Co-precipitation was used to create strontium-doped nano-hydroxyapatite, which was used to make dentifrice. Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) were used to analyze the elements in the recently produced strontium-doped nano-hydroxyapatite. From the extracted tooth's base surface, 30 enamel samples measuring 4 x 4 x 1 mm were created. The mean calcium/phosphorus of all healthy samples and after demineralization were assessed using SEM-EDAX analysis. A new blend of strontium-doped nano-hydroxyapatite was used to remineralize the samples after which the average calcium and phosphorus content was determined. Results When compared to the mean calcium and phosphorus values of the demineralized specimen, the mean calcium and phosphorus values after remineralization using strontium-doped nano-hydroxyapatite were greater and statistically significant (p = 0.001). Using the one-way analysis of variance and Tukey's post hoc test, the mean calcium and phosphorus values of the sound enamel specimen, demineralized specimen, and remineralized specimen were compared. Conclusions The novel strontium-doped hydroxyapatite paste showed good remineralization potential. SEM-EDAX evaluation showed favorable topographic changes in enamel.

Experimental Investigation on the Potential Use of Magnetic Water as a Water Reducing Agent in High Strength Concrete.

High-strength concrete is designed for a self-weight reduction structure and exhibits higher resistance to compressive loads. This paper proposes a novel technique to enhance concrete's properties using Magnetic Field Treated Water (MFTW), describing the results of experimental studies to apprehend the fresh, hardened and microstructural behavior of concrete prepared with Magnetic Water (MW) using a permanent magnet with a field intensity of 0.9 Tesla. The novel scheme focuses on utilizing MW as a water-reducing agent instead of SP to improve the workability of fresh concrete with a 0.38 w/c ratio for achieving M40 grade concrete. Results show a 12% improvement in compressive strength and an 8.9% improvement in split tensile strength compared to normal water (NW) with 1% SP. At 30% cement volume reduction, Magnetic Water Concrete (MWC) performs better than Normal Water Concrete (NWC). Microstructure examination shows that a smaller Calcium Hydrate (CH) crystal is formed with MW and its mineral composition is observed through Energy Dispersive X-ray Analysis (EDAX).

Spatial and vertical distribution of microplastics and their ecological risk in an Indian freshwater lake ecosystem.

This study investigated the spatial and vertical distribution of microplastics (MPs) in the water and sediment samples collected from different locations in Kodaikanal Lake, a very popular tourist location. The lake provides water to placesdownstream. MPs are found in the surface water, surface sediment and core sediment, with their respective values of abundance being 24.42 ± 3.22 items/ l, 28.31 ± 5.29 items/ kg, and 25.91 ± 7.11 items/ kg. Spatially, abundance, colour, type and size of MPs vary in the samples of surface water and sediment. The highest levels of MPs are found in the lakes' outlet region. MPs detected are primarily fibres and fragments 3-5 mm in size with PE and PP being the predominant polymers. Seven sampling points were selected to investigate the vertical distribution of MPs. In the core sediment, the abundance and size of MPs decrease with depth. This probably indicates the presence of more MPs in the recent sediment. The core sediment is dominated by sand silt clay fractions, which facilitates potential downward infiltration of fine MPs. SEM images of MPs reveal that the degree of weathering increases with depth, and EDAX shows that smooth MP surface displays a lesser adhesion ability than the rough surface. Plastic wastes generated by tourism are the important source of MPs in the lake. The lake has high PHI values (>1000) due to MPs with high hazard score polymers (PS and PEU), whereas the PLI values (1.33) indicate low level of MP pollution representing a minor ecological risk. The MP level in Kodaikanal Lake is influenced by the lake's hydrology and the sources of pollution. Although the impacts of MP pollution on the health and functioning of the environment is uncertain, observing, understanding and halting of further MP contamination in the Kodaikanal Lakes is important.

Changes in the proximate and elemental composition of Alitropus typus (Crustacea: Flabellifera: Aegidae) exposed to lethal dose of bacterial consortium.

Alitropus typus is a crustacean parasite, which is increasingly becoming a menace to aquafarmers. In our previous study, a novel microbial consortium comprising of three exoskeleton degrading bacterial strains (Stenotrophomonas maltophilia, Bacillus altitudinis and Klebsiella pneumoniae) had shown promising results as a biocontrol agent for A. typus. The present investigation reports the changes in proximate and elemental composition associated with the application of microbial consortium on the isopod A. typus. Proximate analysis showed an increased level of protein, lipid, and moisture in treated isopod at 48 h compared with untreated isopod. However, ash and chitin concentrations were lower in treated isopod. The elements in the mid-tergite of untreated isopod was compared with the treated isopod at 48 h using scanning electron microscopy and energy dispersive x-ray spectroscopy (SEM-EDAX). The following elements were analyzed in the mid-tergite segment of untreated isopod: C, O, Na, Mg, Al, Si, P, S, Cl, K, Ca and Fe. The results showed that the concentration of calcium had decreased significantly in the treated isopod at 48 h (4.28 ± 0.11%) when compared to the untreated isopod (10.01 ± 0.32%), indicating that the bound form of calcium carbonate in the exoskeleton had been precipitated by microbial action. The concentration of carbon and phosphorous was higher in the treated isopods at 48 h compared to the untreated ones. The data suggests that treatment with microbial consortium is not only an effective but also an environmentally safe alternative for the control of A. typus.

Microplastic contamination in Indian edible mussels (Perna perna and Perna viridis) and their environs.

This study investigated the microplastic (MPs) contamination of the mussels, P. viridis and P. perna of different sizes, and their environment viz. water and sediment. MPs were recovered from the soft tissues of both species. The mean abundance of MPs ranges from 0.87 ± 0.55 to 10.02 ± 4.15 items/individual; 0.1 ± 0.03 to 2.05 ± 0.33 items/g; 31.57 ± 7.63 to 59.25 ± 14.32 items/l in water, and 79.54 ± 18.66 to 108 ± 40.36 items/kg in sediment. Smaller mussels (3-6 cm) are capable of ingesting higher quantities of MPs per gram of tissue weight, and the rate of MP uptake decreases when the mussels grow in size. These might be due to the faster filtration rate in smaller mussels. MPs of fiber type and blue color in the size range of 500 µm to 1 mm are predominant in mussels. Eleven different polymeric groups were identified, of which PE is the most common, followed by PP. The distribution patterns of MP abundance, shape, size, color, and polymer in mussels more closely resemble those in water. There is no significant difference in MP quantities between P. perna and P. viridis (p > 0.05). FTIR-ATR spectroscopy and SEM analysis show that most of the MPs have been strongly weathered. EDAX analysis detects heavy metals like As, Ni, Fe, Zn, and Cd associated with MPs. This study shows that the MPs contents of both the mussel species are transferred from seawater to their edible meat. This study again proved that mussels can act as bio indicator of MPs pollution.

Development of strontium-doped nano hydroxyapatite dentifrice and compare its remineralising potential with a topical cream containing casein phosphopeptide- amorphous calcium phosphate - An In Vitro study.

AIM: To develop and evaluate the efficacy of synthesised strontium-doped nano hydroxyapatite dentifrice and compare its remineralizing potential with a topical cream containing Casein Phospho Peptide - Amorphous Calcium Phosphate, in remineralizing artificial carious lesion on enamel. MATERIALS AND METHODS: Enamel specimens of 4 x 4 x 1 mm were prepared from 90 freshly extracted teeth. Specimens were divided into 3 groups of 30 samples each, based on the type of dentifrice applied that is a control group (Group I) and two experimental groups (Groups II, III). Surface topography and the calcium/phosphorous ratio of all sound specimen were evaluated using Scanning electron microscope and Energy Dispersive X-ray Analysis (SEM-EDAX). The samples in group I and each of the experimental groups were subjected to demineralisation and the calcium/phosphorous ratio of the demineralized specimen were analysed. The samples were then subjected to remineralisation using different agents in each group. Samples in the control group (Group I) were brushed with a conventional dentifrice. In the experimental groups, Group II topical cream with Casein Phosphopeptide and Amorphous Calcium phosphate (CPP-ACP) was used and in Group III laboratory synthesized Strontium-doped nanohydroxyapatite paste (Sr-nHAP), respectively for 28 consecutive days. The samples in the both the control and the two experimental groups were again subjected to SEM-EDAX analysis to analyse the calcium phosphorus ratio following remineralisation cycle. Groupwise comparison of the data was done with one way ANOVA followed by Tukeys Post hoc Test. RESULTS: Both experimental groups (II, III) showed statistically significant remineralisation potential after demineralisation, compared to the control group I. Intergroup comparison showed that the samples in Group III showed the higher remineralisation potential than Group II and was statistically significant. CONCLUSION: Both CPP- ACP containing tooth cream as well as Sr doped nHAp showed remineralisation potential. Sr doped nanohydroxyapatite showed better remineralisation than CPP ACP and can be considered for enamel repair in incipient carious lesions.

Combustion characteristics of briquette fuels from sorghum panicle-pearl millets using cassava starch binder.

The utilization of agricultural wastes is an attractive and viable option to reduce the environmental pollution and reverse the over-exploitation of fossil fuels. Now-a-days, the usage of fossil fuels has increased manifold causing twin serious problems such as depletion of limited source of fossil fuels and increase in environmental pollution with major consequences. In this study, briquettes were produced using sorghum panicles (SP) and pearl millet (PM) with different ratios (100:0, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, 90:10 and 0:100) using cassava starch as a binder with a planned compacting pressure level (200 kN) by exploring hydraulic compression method. The proximate parameters such as water content, level of fixed carbon, ash and volatile matter were determined using American Society for Testing and Materials (ASTM) standard procedures. The elemental analyses (SEM/EDAX) which include carbon (C), oxygen (O), potassium (K), calcium (Ca), chlorine (Cl), sulphur (S), phosphorus (P), aluminium (Al), silicon (Si), magnesium (Mg), cobalt (Co), iron (Fe), zinc (Zn) and sodium (K) were determined in all the briquette samples. Weight loss and optimum heating values of the samples were measured by adopting differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) respectively. In addition to that, the density and compressive strength of all the produced briquettes were determined. In comparison with pongamia-tamarind shell, sorghum panicle-pearl millet briquettes have better fuel properties. The pongamia-tamarind shell fuel has nitrogen and hydrogen whereas sorghum panicle-pearl millet has no identities on both nitrogen and hydrogen content. The occurrence of nitrogen absence is due to non-availability of NOx emissions during combustion. By the cause of more fixed carbon composition, there exists lack in hydrogen content. The sorghum panicle-pearl millet briquettes have better calorific value than pongamia-tamarind shells, and they produce better heating values. Hence, the prepared biomass briquettes are potentially good fuels that derived from agro wastes. Likewise, the determined parameters are compared with the other biomass briquettes.

Nanoparticles of biotite mica as KrishnaVajraAbhraka Bhasma: synthesis and characterization.

BACKGROUND: Bio-inorganic nanoparticles or metal nanoparticles are used in medicine for diagnostic and treatment purposes. The nanomedicines from traditional Ayurvedic system are termed as bhasma. Rasashastra, the branch of inorganic medicines of Ayurveda, has documented monographs of metal-mineral bhasmas as potent drugs. However there is lack of scientific analytical data of the end products. OBJECTIVES: Present study was aimed at finding out the morphological, structural, elemental and chemical composition of the Krishna vajra abhraka bhasma (KVB). MATERIALS AND METHODS: Bhasma of KVB (Biotite Mica) was prepared in our laboratory using biotite mica sheets befitting selection criteria and carrying out further processes with strict SOPs as per AFI. RESULTS: The bhasma complied with the confirmatory tests from Rasashastra. The physical and physicochemical tests correlate with the results obtained by instrumental analytical methods. SEM revealed square shaped nanoparticles of mean size of 92.3 nm. EDAX showed presence of Si, Mg, O, Fe, Ca, Na, C, K and Al. XRD revealed the crystalline nature of bhasma with mixture of various individual oxides and spinel shape of the crystal. DLS showed that the nanoparticles are unimodal in nature. FTIR and NMR showed the organic functional groups obtained from cow milk and selected herbs, indicating unique bio-inorganic nature of the KVB. CONCLUSION: The therapeutic potential imparted to the formulation could be due to the cow milk and specific herbs utilized during the manufacturing process.

Phytoremediation potential of heavy metal accumulator plants for waste management in the pulp and paper industry.

The present manuscript has focused on the heavy metal; accumulation potential by common native plants i.e. Chenopodium album L., Ricinus communis, Ranunculus sceleratus, and Rumex dentatus growing on the disposed of pulp and paper mill effluent sludge. The sludge showed the abundance of benzene propanoic acid tert- butyldimethylsilyl ester, Octadecanoic acid, TMS, Hexadecanoic acid, TMS, cinnamic acid-α-phenyl-TMS ester, ß-sitosterol TMS, 4-mercaptobenzoic acid as residual complex organic compounds along with heavy metals Fe (98.30 mg/L-1), Zn (51.00 mg/L-1), Cu (3.21 mg/L-1), Cd (9.11 mg/L-1), Mn (18.27 mg/L-1), Ni (5.21 mg/L-1), (Hg 0.014 mg/L-1) which were above the prescribed limit of environmental standard. The complexation of organic compounds with heavy metal restricts the bioavailability of metals to plants. But the metal analysis in various parts of the plant showed a significant amount of metal accumulation. Further, histological observations of root tissue through TEM showed apparent deposition of metal granules near the cell wall and vacuole as adoption features of plants. But the variable concentration of metal accumulation in different parts by various plants indicated the variable potential of tested plants with various metals. This also indicated their metal bio-availability and movement to plant tissue. Further, their bioconcentration factor (BCF) and translocation factor (TF) > 1.0 indicated the hyperaccumulation tendency of plants Mn was accumulated maximum in leaves C. album (69.38 mg/kg-1) followed by Cu (25.75 mg/kg -1), As (23.20 mg/kg -1), Fe (20.90 mg/kg -1) and Pb was maximum accumulated (22.41 mg/kg -1) in R. cummunis leaves. The result revealed that arsenic has been accumulated in higher amount root, shoot and leaves of all tested plants. The metal accumulator plants showed phytoremediation potential also by reducing various pollution parameters after growth on sludge. These potential plants may be used as biotechnological tools for the eco-restoration of polluted sites.

Occurrence of microplastics in epipelagic and mesopelagic fishes from Tuticorin, Southeast coast of India.

This study investigated the microplastic (MP) contamination of seawater and fishes from different habitats so as to understand the level of human exposure to microplastics. Samples of Harpodon nehereus, Chirocentrus dorab, Sardinella albella, Rastrelliger kanagurta, Katsuwonus pelamis and Istiophorus platypterus were collected from Tuticorin, southeast coast of India. The MPs in seawater and the gastrointestinal tracts of fish were identified using Stereomicroscope and characterized by FTIR and SEM-EDAX analysis. The abundance of MPs varied from 3.1 ± 2.3 to 23.7 ± 4.2 items L-1 in water, from 0.11 ± 0.06 to 3.64 ± 1.7 items/individual, and from 0.0002 ± 0.0001 to 0.2 ± 0.03 items/g gut weight. The epipelagic fishes had higher levels of MP contamination than the mesopelagic ones. Most of the MPs identified were of blue color, of fiber type and with their size <500 µm. Polyethylene was the most commonly detected MP, followed by polyester and polyamide, and this fact could be attributed to the inflow of domestic sewage and to the intensive fisheries activities in the area. SEM-EDAX spectra revealed the weathered MP surfaces which could adsorb/leach inorganic elements (colorants and fillers) from/to the environment. We may conclude that the concentration of MPs in fishes is a function of the concentration of MPs in their environment.

Profiling microplastics in the Indian edible oyster, Magallana bilineata collected from the Tuticorin coast, Gulf of Mannar, Southeastern India.

The objective of this study is to quantify the extent of microplastic (MP) contamination in the Indian edible oyster (Magallana bilineata) and to understand how this relates to the MP contamination in its surrounding marine environment. Samples of water, sediment and oysters of different sizes were collected from three sites along Tuticorin coast in Gulf of Mannar in Southeast India. The mean abundance of MP in oysters was found to be 6.9 ±â€¯3.84 items/individual and the mean concentration to be 0.81 ±â€¯0.45 items/g of tissue. Polyethylene (PE) and polypropylene (PP) fibers were the dominant MP types in oysters (92% and 4%, respectively) and in seawater (75% and 25%, respectively), with PE fibers, ranging from 0.25 to 0.5 mm, being the most common. Both PE and PP are low-density polymers which are slow to sediment to the seafloor. This increases the potential of their availability in the environment and ingestion by the oysters. The largest oysters (14-16 cm) contained the highest abundance and concentrations of MP, suggesting a greater proportion of MP in the water column is ingested with increasing size. The calculated microplastic index (0.02 to 0.99) also indicates that MP bioavailability increases with increasing size of oysters. The distribution patterns of MP abundance, shape and size in oysters more closely resemble those in water than in sediment. The surface morphology of the MPs reveals the characteristic pits and cracks which result from partial degradation through the weathering processes. Energy-dispersive X-ray spectroscopy analysis shows the presence of Ni and Fe in association with MP, and this probably indicates the fly-ash pollution and the petroleum-related activities in the surrounding area. Being sessile animals the oysters are good candidates for use as sentinel organisms for monitoring MP in specific marine environments.

Abundance, characteristics and surface degradation features of microplastics in beach sediments of five coastal areas in Tamil Nadu, India.

This study undertook to investigate the occurrence of microplastics (MPs) in the high and low-tide sediments of five coastal areas in Tamil Nadu, India. The abundance of microplastics vary from 439 ±â€¯172 to 119 ±â€¯72 (HTL) and 179 ±â€¯68 to 33 ±â€¯30 (LTL) items kg-1 of sediments. The MP polymers found in the study sites are Polyethylene (73.2%), polypropylene (13.8%), nylon (8.2%), polystyrene (2.8%) and polyester (2%). The weathered surfaces might act as high-capacity carriers and this was confirmed by SEM-EDAX. The results of an analysis of the textures of the sediments do not ascribe any influence on microplastic abundance. The recreation, religious and fishing activities are the major contributors to plastic pollution in these beaches, which is borne out by the high abundance of MPs in the study sites. A regular and permanent waste management system should be put in place for the protection of beaches.

The Evaluation of Damage Effects on MgO Added Concrete with Slag Cement Exposed to Calcium Chloride Deicing Salt.

Concrete systems exposed to deicers are damaged in physical and chemical ways. In mitigating the damage from CaCl2 deicers, the usage of ground slag cement and MgO are investigated. Ordinary Portland cement (OPC) and slag cement are used in different proportions as the binding material, and MgO in doses of 0%, 5%, 7%, and 10% are added to the systems. After 28 days of water-curing, the specimens are immersed in 30% CaCl2 solution by mass for 180 days. Compressive strength test, carbonation test, chloride penetration test, chloride content test, XRD analysis, and SEM-EDAX analysis are conducted to evaluate the damage effects of the deicing solution. Up to 28 days, plain specimens with increasing MgO show a decrease in compressive strength, an increase in carbonation resistance, and a decrease in chloride penetration resistance, whereas the S30- and S50- specimens show a slight increase in compressive strength, an increase in carbonation resistance, and a slight increase in chloride penetration resistance. After 180 days of immersion in deicing solution, specimens with MgO retain their compressive strength longer and show improved durability. Furthermore, the addition of MgO to concrete systems with slag cement induces the formation of magnesium silicate hydrate (M-S-H) phases.

Synthesis, characterization and optical properties of polymer-based ZnS nanocomposites.

Nanostructured polymer-semiconductor hybrid materials such as ZnS-poly(vinyl alcohol) (ZnS-PVA), ZnS-starch and ZnS-hydroxypropylmethyl cellulose (Zns-HPMC) are synthesized by a facile aqueous route. The obtained nanocomposites are characterized using various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV/vis spectroscopy and photoluminescence (PL). XRD studies confirm the zinc blende phase of the nanocomposites and indicate the high purity of the samples. SEM studies indicate small nanoparticles clinging to the surface of a bigger particle. The Energy Dispersive Analysis by X-rays (EDAX) spectrum reveals that the elemental composition of the nanocomposites consists primarily of Zn:S. FTIR studies indicate that the polymer matrix is closely associated with ZnS nanoparticles. The large number of hydroxyl groups in the polymer matrix facilitates the complexation of metal ions. The absorption spectra of the specimens show a blue shift in the absorption edge. The spectrum reveals an absorption edge at 320, 310 and 325 nm, respectively. PL of nanocomposites shows broad peaks in the violet-blue region (420-450 nm). The emission intensity changes with the nature of capping agent. The PL intensity of ZnS-HPMC nanocomposites is found to be highest among the studied nanocomposites. The results clearly indicate that hydroxyl-functionalized HPMC is much more effective at nucleating and stabilizing colloidal ZnS nanoparticles in aqueous suspensions compared with PVA and starch.

Recent advances in the use of graphene-family nanoadsorbents for removal of toxic pollutants from wastewater.

Adsorption technology is widely considered as the most promising and robust method of purifying water at low cost and with high-efficiency. Carbon-based materials have been extensively explored for adsorption applications because of their good chemical stability, structural diversity, low density, and suitability for large scale production. Graphene--a single atomic layer of graphite--is the newest member in the family of carbon allotropes and has emerged as the "celeb" material of the 21st century. Since its discovery in 2004 by Novoselov, Geim and co-workers, graphene has attracted increased attention in a wide range of applications due to its unprecedented electrical, mechanical, thermal, optical and transport properties. Graphene's infinitely high surface-to-volume ratio has resulted in a large number of investigations to study its application as a potential adsorbent for water purification. More recently, other graphene related materials such as graphene oxide, reduced graphene oxide, and few-layered graphene oxide sheets, as well as nanocomposites of graphene materials have also emerged as a promising group of adsorbent for the removal of various environmental pollutants from waste effluents. In this review article, we present a synthesis of the current knowledge available on this broad and versatile family of graphene nanomaterials for removal of dyes, potentially toxic elements, phenolic compounds and other organic chemicals from aquatic systems. The challenges involved in the development of these novel nanoadsorbents for decontamination of wastewaters have also been examined to help identify future directions for this emerging field to continue to grow.

Gum kondagogu reduced/stabilized silver nanoparticles as direct colorimetric sensor for the sensitive detection of Hg²âº in aqueous system.

A highly sensitive and selective method is reported for the colorimetric detection of Hg(2+) in aqueous system by using label free silver nanoparticles (Ag NPs). Ag NPs used in this method were synthesized by gum kondagogu (GK) which acted as both reducing and stabilizing agent. The average size of the GK-Ag NPs was found to be 5.0 ± 2.8 nm as revealed by transmission electron microscope (TEM) analysis and the nanoparticles were stable at various pH conditions (pH 4-11) and salt concentrations (5-100 mM). The GK reduced/stabilized Ag NPs (GK-Ag NPs) were directly used for the selective colorimetric reaction with Hg(2+) without any further modification. The bright yellow colour of Ag NPs was found to fade in a concentration dependent manner with the added Hg(+) ions. The fading response was directly correlated with increasing concentration of Hg(2+). More importantly, this response was found to be highly selective for Hg(2+) as the absorption spectra were found to be unaffected by the presence of other ions like; Na(+), K(+), Mg(2+), Ca(2+), Cu(2+), Ni(2+), Co(2+), As(3+), Fe(2+), Cd(2+), etc. The metal sensing mechanism is explained based on the turbidometric and X-ray diffraction (XRD) analysis of GK-Ag NPs with Hg(2+). The proposed method was successfully applied for the determination of Hg(2+) in various ground water samples. The reported method can be effectively used for the quantification of total Hg(2+) in samples, wherein the organic mercury is first oxidized to inorganic form by ultraviolet (UV) irradiation. The limit of quantification for Hg(2+) using the proposed method was as low as 4.9 × 10(-8) mol L(-1) (50 nM). The proposed method has potential application for on-field qualitative detection of Hg(2+) in aqueous environmental samples.

Chalcone embedded polyurethanes as a biomaterial: Synthesis, characterization and antibacterial adhesion.

An antibacterial dimethylamino-chalcone embedded multiblock copolymer (PCL-PEG) was synthesized and characterized using FT-IR, 1H NMR, SEM and SEC and the compound was characterized using FT-IR, 1H NMR, and 13C NMR. A 10% copolymer composite was prepared and casted as film to be used as a biomaterial and the copolymer films without the compound acted as control. TGA, DSC, AFM, SEM and EDAX analysis were performed for the above samples. Surface roughness (Ra) of the copolymer composite film was less when compared to the copolymer film which indicated the proper distribution of chalcone in the composite film. copolymer composite film was hydrophilic compared to copolymer film. Antibacterial adhesion studies were performed for copolymer composite polymer film and evaluated using CFU measurement and SEM analysis. Copolymer composite film shows promising antibacterial adhesion compared to the copolymer film. Hence the copolymer composite film can be used as a new biomaterial endowed with antibacterial properties.