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Water, the driver of nature, has always been polluted by the blind hurling of highly toxic contaminants, but human-friendly science has continuously been presenting better avenues to help solve these challenging issues. In this connection, the present study introduces novel nanocomposites composed of emulsion-templated hierarchically porous poly(1-vinylimidazole) beads loaded with the silver nanoparticles generated via an in situ approach. These nanocomposites have been thoroughly characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer-Emmett-Teller, and field emission scanning electron microscopy. The appropriate surface chemistry, good thermal stability, swelling behavior, porosity, and nanodimensions contributed to achieve very good performance in water treatment. Owing to their easier handling and separation, these novel nanocomposites are highly efficient to remove arsenic and eriochrome black T with decent adsorption capacities in addition to the inactivation and killing of Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria.

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A sustainable future demands innovative breakthroughs in science and technology today, especially in the energy sector. Earth‐abundant resources can be explored and used to develop renewable and sustainable resources of energy to meet the ever‐increasing global energy demand. Efficient solar‐powered conversion systems exploiting inexpensive and robust catalytic materials for the photo‐ and photo‐electro‐catalytic water splitting, photovoltaic cells, fuel cells, and usage of waste products (such as CO2) as chemical fuels are appealing solutions. Many electrocatalysts and nanomaterials have been extensively studied in this regard. Low overpotentials, catalytic stability, and accessibility remain major challenges. Metal nanoclusters (NCs, ≤3 nm) with dimensions between molecule and nanoparticles (NPs) are innovative materials in catalysis. They behave like a “superatom” with exciting size‐ and facet‐dependent properties and dynamic intrinsic characteristics. Being an emerging field in recent scientific endeavors, metal NCs are believed to replace the natural photosystem II for the generation of green electrons in a viable way to facilitate the challenging catalytic processes in energy‐conversion schemes. This Review aims to discuss metal NCs in terms of their unique physicochemical properties, possible synthetic approaches by wet chemistry, and various applications (mostly recent advances in the electrochemical and photo‐electrochemical water splitting cycle and the oxygen reduction reaction in fuel cells). Moreover, the significant role that MNCs play in dye‐sensitized solar cells and nanoarrays as a light‐harvesting antenna, the electrochemical reduction of CO2 into fuels, and concluding remarks about the present and future perspectives of MNCs in the frontiers of surface science are also critically reviewed.

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Tainting of waterbodies with noxious industrial waste is the gravest environmental concern of the day that continues to wreak inevitable havoc on human health. To cleanup these hard-to-remove life-threatening water contaminants, we have prepared hierarchically porous poly(acrylic acid) beads by emulsion templating. These emulsion-templated macroporous polymer beads not only mediate the synthesis of Fe 3 O 4 nanoparticles inside their porous network using a coprecipitation approach but, in turn, create diverse anchoring sites to immobilize an additional poly(acrylic acid) active layer onto the nanocomposite beads. These post-synthetically modified nanocomposite beads with macropores and abundant acrylic acid moieties offer the ready mass transfer and fair advantage of relatively higher overall negative charge to efficiently adsorb lead [Pb(II)] and crystal violet with impressive performanceeven superior to many of the materials explored in this regard so far. Furthermore, the strong entanglement of nanoparticles in the porous polymeric scaffolds tackles the curb of trade-off between all-round effective remediation and secondary pollution and the millimeter size eases their processing and recovery during the adsorption tests, thereby making these materials practically worthwhile.

The biogenesis of silver nanoparticles by fungi is an ecologically clean and nontoxic method compared to other physical and chemical methods. Thus, we aimed to discuss the mycosynthesis of extracellular size-controlled AgNPs. After comprehensive screening, Aspergillus fumigatus BTCB10 (KY486782) was selected for the synthesis of AgNPs of controlled size. Characterization was performed by UV-Vis spectrophotometer, Zetasizer, X-Ray Diffraction (XRD), FTIR (Fourier-transform infrared), Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM) along with functional assays—antibacterial and MTT assays. Data suggested that under optimized conditions, i.e., temperature 25°C, AgNO3 concentration 1 mM, biomass 7 g, fungal culture age 7 days, pH 6, ratio of cell-free filtrate (CFF)/silver nitrate (3 : 2), NaCl 20%, and under dark light, the smallest size AgNPs of 0.681 nm with 100% monodispersity was obtained as evident by a zeta potential of -23.4 mV, UV-Vis band at 400 nm, and the presence of O-H and C=O groups confirmed by ATR-FTIR; XRD revealed the crystalline nature of AgNPs; additionally, cube-shaped AgNPs were revealed by Scanning Electron Microscopy (SEM). Moreover, synthesized AgNPs exhibited antibacterial activity against multidrug-resistant bacterial strains, notably, Klebsiella pneumoniae BTCB04, Acinetobacter BTCB05, Pseudomonas aeruginosa BTCB01, and Escherichia coli BTCB03, while maximum 7-fold was observed with Acinetobacter BTCB05. AgNPs demonstrated no cytotoxic activity against HepG2 cells; however, in combination with cisplatin, antiproliferative and cytotoxic effects became more evident and significant in comparison to control and as single agent. Taken together, the data suggested that economical and smallest size AgNPs can be biosynthesized from Aspergillus fumigatus BTCB10 and be used as antibacterial and antiproliferative agents in combination with current drugs against clinically relevant multiple drug-resistant bacterial and tumoral cells. Further studies are required to confirm their effects employing in vivo disease models.

A cadmium-resistant bacterium was isolated from industrial wastewater and identified as Escherichia coli (dubbed as P4) on the basis of morphological, biochemical tests and 16S rRNA ribotyping. It showed optimum growth at 30 °C and pH 7. E. coli P4 found to resist Cd(+2) (10.6 mM) as well as Zn(+2) (4.4 mM), Pb(+2) (17 mM), Cu(+2) (3.5 mM), Cr(+6) (4.4 mM), As(+2) (10.6 mM), and Hg(+2) (0.53 mM). It could remove 18.8, 37, and 56 % Cd(+2) from aqueous medium after 48, 96, and 144 h, respectively. Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and Energy-dispersive X-ray (EDX) analysis also confirmed the biosorption of Cd(+2) by E. coli P4. However, temperature and pH were found to be the most critical factors in biosorption of Cd(+2) by E. coli P4. Cd(+2) stress altered E. coli P4 cell physiology analyzed by measuring glutathione (GSH) and non-protein thiol (cysteine) levels which were increased up to 130 and 48 %, respectively. Quantitative real-time polymerase chain reaction (qRT-PCR) showed alteration in the expression levels of ftsZ, mutS, clpB, ef-tu, and dnaK genes in the presence of Cd(+2). Total protein profiles of E. coli P4 in the absence and presence of Cd(+2) were compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), which showed remarkable difference in the banding pattern. czcB gene, a component of czcCBA operon, was amplified from genomic DNA which suggested the chromosomal-borne Cd(+2) resistance in E. coli P4. Furthermore, it harbors smtAB gene which plays a significant role in Cd(+2) resistance.