Efficient removal of chromate from wastewater using a one-pot synthesis of chitosan cross-linked ceria incorporated hydrous copper oxide bio-polymeric composite.

Remediating hexavalent chromium [Cr(VI)] from contaminated water systems is a significant concern due to its harmful effects on human health, aquatic life, and plants. To tackle this issue, scientists have created a chitosan cross-linked hydrous ceria incorporated cupric oxide bio-polymeric composite (CHCCO) by combining chitosan biopolymer with corresponding metal ions using glutaraldehyde as a cross-linker. The composite was characterized using advanced analytical instruments such as FTIR, p-XRD, SEM, XPS, etc. The synthesized composite (CHCCO) was then tested for its efficiency in removing Cr(VI) from synthetic Cr(VI) aqueous samples. The parameters examined included pH, material dose, contact time, concentration, temperature, and co-existing ions. The experimental data showed that the kinetics and equilibrium data fit well with the pseudo-second-order and the Freundlich isotherm models, respectively. Thermodynamic analysis demonstrated that the investigated surface adsorption process is spontaneous and endothermic. Except for the SO42- ion, no other species imparts adverse influence significantly on the reaction. The CHCCO bio-composite surfaces were refreshed using a dilute NaOH (1.0 M) solution and effectively recycled five times for Cr(VI) adsorption, indicating no significant surface activity deterioration. This study highlights the high effectiveness of CHCCO bio-polymeric composites in Cr(VI) remediation and the potential for this technology as an easy-to-use technique for environmental restoration.

Ecological restoration at pilot-scale employing site-specific rationales for small-patch degraded mangroves in Indian Sundarbans.

To date, degraded mangrove ecosystem restoration accomplished worldwide primarily aligns towards rehabilitation with monotypic plantations, while ecological restoration principles are rarely followed in these interventions. However, researchers admit that most of these initiatives' success rate is not appreciable often. An integrative framework of ecological restoration for degraded mangroves where site-specific observations could be scientifically rationalized, with co-located reference pristine mangroves as the target ecosystem to achieve is currently distinctively lacking. Through this experimental scale study, we studied the suitability of site-specific strategies to ecologically restore degraded mangrove patches vis-à-vis the conventional mono-species plantations in a highly vulnerable mangrove ecosystem in Indian Sundarbans. This comprehensive restoration framework was trialed in small discrete degraded mangrove patches spanning ~ 65 ha. Site-specific key restoration components applied are statistically validated through RDA analyses and Bayesian t-tests. 25 quantifiable metrics evaluate the restoration success of a ~ 3 ha degraded mangrove patch with Ridgeline distribution, Kolmogorov-Smirnov (K-S) tests, and Mahalanobis Distance (D2) measure to prove the site's near-equivalence to pristine reference in multiple ecosystem attributes. This restoration intervention irrevocably establishes the greater potential of this framework in the recovery of ecosystem functions and self-sustenance compared to that of predominant monoculture practices for vulnerable mangroves.

Estuarine mangrove niches select cultivable heterotrophic diazotrophs with diverse metabolic potentials-a prospective cross-dialog for functional diazotrophy.

Introduction: Biological nitrogen fixation (BNF), an unparalleled metabolic novelty among living microorganisms on earth, globally contributes ~88-101 Tg N year-1 to natural ecosystems, ~56% sourced from symbiotic BNF while ~22-45% derived from free-living nitrogen fixers (FLNF). The success of symbiotic BNF is largely dependent on its interaction with host-plant, however ubiquitous environmental heterotrophic FLNFs face many limitations in their immediate ecological niches to sustain unhindered BNF. The autotrophic FLNFs like cyanobacteria and oceanic heterotrophic diazotrophs have been well studied about their contrivances acclimated/adapted by these organisms to outwit the environmental constraints for functional diazotrophy. However, FLNF heterotrophs face more adversity in executing BNF under stressful estuarine/marine/aquatic habitats. Methods: In this study a large-scale cultivation-dependent investigation was accomplished with 190 NCBI accessioned and 45 non-accessioned heterotrophic FLNF cultivable bacterial isolates (total 235) from halophilic estuarine intertidal mangrove niches of Indian Sundarbans, a Ramsar site and UNESCO proclaimed World Heritage Site. Assuming ~1% culturability of the microbial community, the respective niches were also studied for representing actual bacterial diversity via cultivation-independent next-generation sequencing of V3-V4 rRNA regions. Results: Both the studies revealed a higher abundance of culturable Gammaproteobacteria followed by Firmicutes, the majority of 235 FLNFs studied belonging to these two classes. The FLNFs displayed comparable selection potential in media for free nitrogen fixers and iron-oxidizing bacteria, linking diazotrophy with iron oxidation, siderophore production, phosphorus solubilization, phosphorus uptake and accumulation as well as denitrification. Discussion: This observation validated the hypothesis that under extreme estuarine mangrove niches, diazotrophs are naturally selected as a specialized multidimensional entity, to expedite BNF and survive. Earlier metagenome data from mangrove niches demonstrated a microbial metabolic coupling among C, N, P, S, and Fe cycling in mangrove sediments, as an adaptive trait, evident with the co-abundant respective functional genes, which corroborates our findings in cultivation mode for multiple interrelated metabolic potential facilitating BNF in a challenging intertidal mangrove environment.

Fluorenyl-tethered N-heterocyclic carbene (NHC): an exclusive C-donor ligand for heteroleptic calcium and strontium chemistry.

Exclusive C-donating ligands are rarely used with kinetically labile heavier alkaline earths (Ca, Sr, Ba). We report herein the aptitude of a combination of NHC with fluorenyl connected by a flexible -(CH2)2- linker as a ligand support for heteroleptic Ca- and Sr-N(SiMe3)2 and iodides. The Ca-N(SiMe3)2 complex even catalyzes the intramolecular hydroamination of aminoalkenes to showcase the effectiveness of this ligand framework.

A N-Heterocyclic Carbene-Supported Zinc Catalyst for the 1,2-Regioselective Hydroboration of N-Heteroarenes.

A fluorenyl-tethered N-heterocyclic carbene LH (LH=[(Flu)H-(CH2 )2 -NHCDipp ]) and its monoanionic version L- are explored in complexation with zinc towards the hydroboration of N-heteroarenes, carbonyl, ester, amide, and nitrile under ambient condition. The N-heteroarenes exhibit high 1,2-regioselectivity which is justified by computational analyses. The relative hydroboration rates of differently p-substituted (electron donating vs. withdrawing) pyridines are also addressed. The monodentate LH offers a better catalytic activity than the chelating L- for steric reasons despite both giving three-coordinate zinc complexes. The mechanism involves a Zn-H species at the heart of these catalytic processes which is trapped by Ph2 CO. Computational studies suggest that the barrier to form the hydride complex is comparable to the barrier required for the following hydride transfer to pyridine.

Cyclopentadienyl Complexes of the Alkaline Earths in Light of the Periodic Trends.

The electron-rich cyclopentadienyl and the analogous indenyl and fluorenyl ligands (collectively denoted here as Cp') have been impactful in stabilizing electron-deficient metal centers including the highly electropositive alkaline earths. Being in the s-block, the group 2 metals follow a major periodic variation in their atomic and ionic properties which is reflected in those Cp' compounds. This article presents an overview of this class of compounds for all the five metals from beryllium to barium (radium is excluded for its radioactivity), highlighting their systematic variation.

Exploring role of polysaccharides present in Ganoderma lucidium extract powder and probiotics as solid carriers in development of liquisolid formulation loaded with quercetin: A novel study.

Ganoderma lucidium extract powder (GLEP) contains various polysaccharides which are well known for their antioxidant and anti-inflammatory actions. Probiotics (PB) are well-established for providing a plethora of health benefits. Hence, use of mushroom polysaccharides and probiotics as carriers to solidify liquisolid formulation is anticipated to function as functional excipients i.e. as adsorbent that may provide therapeutic benefits. Quercetin (QUR) has been used as model lipophilic drug in this study. QUR loaded liquisolid compacts (LSCs) were formulated using Tween 80 as solvent. These were further solidified using a combination of PB and GLEP as carriers. Aerosil-200 (A-200) was used as coating agent. The formulation exhibited very good flow characteristics. Dissolution rate of raw QUR was found to be less than 10% in 60 min while in case of QUR loaded LSCs, more than 90% drug release was observed within 5 min. Absence of crystalline peaks of QUR in the DSC and PXRD reports of LSCs and their porous appearance in SEM micrographs indicate that QUR was successfully incorporated in the LSCs. The developed formulation was found to be stable on storage under accelerated stability conditions.

Chemical Synthesis of Biosurfactant Succinoyl Trehalose Lipids.

Herein, we report, for the first time, a strategy to differentiate O4/O4' positions of 1,1'-α,α-trehalose via regioselective protection or site-selective functionalization and its application in the first chemical synthesis of succinoyl trehalose lipids. The biosurfactant glycolipids were obtained in 11-12 steps starting from trehalose in time span of 8-10 days and 11-12% overall yields.