Rapid biosynthesis and characterization of metallic gold nanoparticles by olea europea and their potential application in photoelectrocatalytic reduction of 4-nitrophenol.

In recent years, photoelectrocatalysis of gold nanoparticles (Au NPs) has received considerable attention due to their potential to improve catalytic efficiency. Herein, ultra-small Au NPs were successfully synthesized in a single pot using olea europea leaf extract as a green reducing agent for the degradation of 4-nitrophenol. The TEM images showed uniform distribution and spherical shape of Au NPs with an average diameter of 5 nm. Taking advantage of the ability of Au nanoparticles to absorb visible and near-infrared light, 4-nitrophenol can be successfully reduced in the presence of NaBH4. Additionally, the electrochemical activity of the fabricated Au photocathode was investigated by linear sweep voltammetry in the dark and at VIS-NIR light irradiation. This showed an increased photocurrent density of 27 mA cm-2 with an onset potential of -0.71 V. This indicates that the Au photocathode is highly active at VIS-NIR light. Interestingly, the Au photocathode showed a higher current density of 37 mA cm-2 with an onset potential of -0.6 V in the presence of 4-nitrophenol during VIS-NIR irradiation, indicating that 4-nitrophenol was efficiently reduced by the photocathode. The Au photocathode completely reduced 4-nitrophenol in the wastewater within 35 min. Recyclability studies showed that the Au NPs photocathode exhibited higher stability over multiple cycles, confirming the ability of the electrode to treat wastewater over a longer period of time. This study demonstrates the effectiveness of the photoelectrochemical (PEC) process in reducing organic compounds in wastewater.

Hybrid capacitive deionization of NaCl and toxic heavy metal ions using faradic electrodes of silver nanospheres decorated pomegranate peel-derived activated carbon.

Capacitive deionization (CDI) is an evolving technology for eradicating salt and toxic heavy metal ions from brackish wastewater. However, traditional CDI electrodes have lower salt adsorption capacity and inadequate adsorption of selective metal ions for long-term operations. Herein, Ag nanospheres incorporated pomegranate peel-derived activated carbon (Ag/P-AC) was prepared and implied to the CDI process for removing NaCl, toxic mono-, di-, and trivalent metal ions. Morphological analysis revealed that the 80-100 nm-sized Ag nanospheres were uniformly decorated on the surfaces of P-AC nanosheets. The Ag/P-AC has a higher specific surface area (640 m2 g-1), superior specific capacitance (180 F g-1 at 50 mV s-1) and a lower charge transfer resistance (0.5 Ω cm2). CDI device was fabricated by Ag/P-AC as an anode, which adsorbed anions and P-AC as cathode for adsorption of positively charged ions at 1.2 V in an initial salt concentration of 1000 mg L-1. An asymmetric Ag/P-AC//P-AC exhibited a maximum NaCl adsorption capacity of 36 mg g-1 than symmetric P-AC//P-AC electrodes (22.7 mg g-1). Furthermore, Pb(II), Cd(II), F-, and As(III) ions were successfully removed from simulated wastewater by using Ag/P-AC//P-AC based CDI system. These asymmetric CDI-electrodes have an excellent prospect for the removal of salt and toxic contaminants in industrial wastewater.

An efficient and magnetically recoverable g-C3N4/ZnS/CoFe2O4 nanocomposite for sustainable photodegradation of organic dye under UV-visible light illumination.

Effective improvement of an easily recoverable photocatalyst is equally vital to its photocatalytic performance from a practical application view. The magnetically recoverable process is one of the easiest ways, provided the photocatalyst is magnetically strong enough to respond to an external magnetic field. Herein, we prepared graphitic carbon nitride nanosheet (g-C3N4), and ZnS quantum dots (QDs) supported ferromagnetic CoFe2O4 nanoparticles (NPs) as the gC3N4/ZnS/CoFe2O4 nanohybrid photocatalyst by a wet-impregnation method. The loading of CoFe2O4 NPs in the g-C3N4/ZnS nanohybrid resulted in extended visible light absorption. The ferromagnetic g-C3N4/ZnS/CoFe2O4 nanohybrid exhibited better visible-light-active photocatalytic performance (97.11%) against methylene blue (MB) dye, and it was easily separable from the aqueous solution by an external bar magnet. The g-C3N4/ZnS/CoFe2O4 nanohybrid displayed excellent photostability and reusability after five consecutive cycles. The favourable band alignment and availability of a large number of active sites affected the better charge separation and enhanced photocatalytic response. The role of active species involved in the degradation of MB dye during photocatalyst by g-C3N4/ZnS/CoFe2O4 nanohybrid was also investigated. Overall, this study provides a facile method for design eco-friendly and promising g-C3N4/ZnS/CoFe2O4 nanohybrid photocatalyst as applicable in the eco-friendly dye degradation process.

Adsorptive removal of noxious atrazine using graphene oxide nanosheets: Insights to process optimization, equilibrium, kinetics, and density functional theory calculations.

Atrazine is a toxic herbicide whose alarming rate of contamination in the drinking water and wastewater poses a severe threat to the environment and human health. Here in this study, the graphene oxide (GO) nanosheets were prepared using Hummers' method with minor modification and studied as a potential adsorbent for atrazine removal from simulated wastewater. The spectroscopy and microscopic analysis confirmed the successful formation of GO with a multilayer structure resembling the crumpled sheets with random stacking. The Response Surface Methodology (RSM) employing Box Behnken design (BBD) was successfully developed to predict the optimal conditions for maximal atrazine removal as adsorbent dosage 121.45 mg/L; initial feed concentration 27.03 mg/L; temperature 27.69 °C, pH 5.37, and time 180 min. The atrazine adsorption onto GO was found to be higher in acidic pH and lower temperature. Density functional theory (DFT) calculation of adsorbent-adsorbate complex in the implicit solvent medium suggests adsorption affinity energy of -24.4 kcal/mol for atrazine. A careful observation of the molecules configuration and binding energy showed that the π-π interactions and hydrogen bonds played a significant role in the adsorption phenomena. Langmuir isotherm suited well to the adsorption process with a maximum adsorption capacity of 138.19 mg/g, at 318 K. The fitness of kinetic models for atrazine adsorption onto GO nanosheets were in following order Ho < Sobkowsk-Czerwi < Avrami model based on their correlation coefficient (R2) values. Reusability analysis showed that GO nanosheets could be effectively recycled using 0.01 N NaOH up to six cycles of atrazine removal. Thus, this study provided a theoretical and experimental basis for the potential application of GO nanosheets as a novel adsorbent for the removal of hazardous atrazine.

Biosorption performance of date palm empty fruit bunch wastes for toxic hexavalent chromium removal.

Biosorption ability of date palm empty fruit bunch (DPEFB) was examined for the removal of toxic hexavalent chromium (Cr6+) ions from synthetic wastewater. The pretreated DPEFB biosorbent was studied for its morphology and surface chemistry through Scanning electron microscopy, Energy dispersive elemental analysis and Fourier transform infrared spectroscopy. Effect of biosorption parameters such as pH, biosorbent dosage, contact time, temperature, initial feed concentration and agitation speed on the Cr6+ ions removal efficiency by DPEFB was critically evaluated. The isoelectric point for the DPEFB sorbent was observed at pH 2, above which it was dehydronated to capture the positively charged Cr6+ ions. Batch biosorption studies showed that an optimal chromium removal efficiency of 58.02% was recorded by the DPEFB biosorbent for pH 2, dosage 0.3 g, 100 rpm agitation speed, 120 min contact time, 50 mg/L initial feed concentration and 30 °C operational temperature. Thermodynamic analysis showed that the binding of Cr6+ ions on DPEFB surface was exothermic, stable and favorable at room temperature. Equilibrium behavior of chromium binding on DPEFB was more aligned to Temkin isotherm (R2 = 0.9852) highlighting the indirect interactions between Cr6+ ions and the biosorbent. Kinetic modeling revealed that the biosorption of Cr6+ ions by DPEFB obeyed pseudo-second order model than the pseudo-first order and intra-particle diffusion models. Reusability studies of the DPEFB sorbent showed that NaNO3 was an effective regenerant and the biosorbent can be efficiently reused up to three successive biosorption-desorption cycles for chromium removal. In summary, the results clearly showed that the DPEFB biowaste seems to be an efficient, economic and eco-friendly biosorbent for sustainable removal of toxic hexavalent chromium ions from domestic and industrial wastewater streams.

Synthesis of novel triazole/isoxazole functionalized 7-(trifluoromethyl)pyrido[2,3-d]pyrimidine derivatives as promising anticancer and antibacterial agents.

A series of novel 1,2,3-triazole/isoxazole functionalized pyrido[2,3-d]pyrimidine derivatives 6a-c, 7a-h and 8a-e were prepared in series of synthetic steps. All the compounds screened for the anticancer activity against four human cancer cell lines using Nocodazole as standard. Compounds 7d and 7h showed highest activity against PANC-1 (pancreatic cancer) and A549 (lung cancer) cell lines respectively and more than standard. All the compounds also screened for antibacterial activity using Rifampicin and Ciprofloxacin as standards and identified promising compounds further evaluated for minimum inhibitory concentration to validate the data.

Valorization of date palm leaves for adsorptive remediation of 2,4-dichlorophenoxyacetic acid herbicide polluted agricultural runoff.

Alarming rates of water contamination by toxic herbicides have prompted the need and attention for easy, efficient, and affordable treatment options with a touch of circular economy aspects. This study valorized date palm leaf (DPL) wastes into a valuable adsorbent for remediating agricultural wastewater polluted with 2,4-Dichlorophenoxyacetic acid (2,4-DPA) herbicide. The DPL precursor was modified with H2SO4 treatment and both biomass samples were characterized by various analytical techniques. Acid treatment modified the morphology, thermal, and textural properties of the final product (TDPL) while maintaining the structure and surface chemistry intact. Simulated wastewaters containing 2,4-DPA were subsequently treated using TDPL as an adsorbent. Optimum adsorption conditions of pH 2, dosage 0.95 g/L, shaking speed 200 rpm, time 120 min, and temperature 30 °C showed a good herbicide removal efficiency in the range of 55.1-72.6% for different initial feed concentrations (50-250 mg/L). Experimental kinetic data were better represented by the pseudo-second-order model, while the Freundlich isotherm was reliable in describing the equilibrium behavior of the adsorption system. Further, the thermodynamic analysis revealed that the adsorption occurred spontaneously, favorably, and exothermically. Plausible sorption mechanism involved electrostatic interactions, weak van der Waals forces, hydrogen bonds, and π-π interactions between the participating phases. Conspicuously, TDPL application to real-world situations of treating actual herbicide-polluted agricultural runoff resulted in a 69.4% remediation efficiency. Thus, the study demonstrated the valorization of date palm leaves into a valuable and industry-ready adsorbent that can sequester toxic 2,4-DPA herbicide contaminant from aqueous streams.

An advanced photo-oxidation process for pharmaceuticals using plasmon-assisted Ag-CoFe2O4 photocatalysts.

The discharge of amoxicillin (AMX) from pharmaceutical intermediates has adverse effects on aquatic ecosystems. The elimination of AMX requires advanced oxidation processes (AOPs) that utilize high-performance photocatalysts. Furthermore, the design of highly visible light photocatalysts for AOPs demands both cost-effectiveness and efficiency. In this work, a plasmon-assisted visible light photocatalyst of 2D Ag-CoFe2O4 nanohybrids was successfully synthesized and characterized with several analytical tools to degrade AMX in aqueous solutions through advanced AOPs. The results showed that the Ag-CoFe2O4 nanohybrids had excellent photocatalytic activity and stability, which could efficiently reduce the AMX concentration by 99% within 70 min under visible light irradiation. In particular, CoFe2O4 and Ag have an interfacial contact that prevents electron-hole pair recombination more effectively than pure CoFe2O4, which results in electrons in its conduction band (CB) migrating to metallic Ag sites. Thus, charge transfers between the two materials are more efficient, leading to higher photocatalytic oxidation of AMX. Furthermore, the surface plasmon of Ag nanoparticles are excited by their plasmonic resonance, which increases the absorption of visible light. The plasmon-assisted visible light photocatalyst could replace expensive and energy-intensive advanced oxidation processes (AOPs). AOPs pathways associated with AMX have been discussed in detail. The HPLC chromatogram clearly showed AMX was oxidized by four-membered B-lactam ring opening and hydroxylation with •OH. 2D Ag-CoFe2O4 heterostructure was found to be efficient, selective, and cost-effective for the degradation of several pharmaceutical compounds. Additionally, it was found to be eco-friendly and sustainable, making it a viable alternative to AOPs.

Enhanced water permeability and fouling resistance properties of ultrafiltration membranes incorporated with hydroxyapatite decorated orange-peel-derived activated carbon nanocomposites.

Hydroxyapatite-decorated activated carbon (HAp/AC) nanocomposite was synthesized and utilized as a nanofiller to fabricate a novel type of polyethersulfone (PES) nanocomposite ultrafiltration (UF) membranes. Activated carbon (AC) derived from orange peel was synthesized by low-temperature pyrolysis at 400 °C. A hydroxyapatite/AC (HAp/AC) nanocomposite was developed by a simple one-pot hydrothermal synthesis method. The UF membrane was fabricated by intercalating HAp/AC fillers into PES casting solution by the non-solvent induced phase separation (NIPS) process. The prepared membranes exhibited a lower water contact angle than the pristine PES membrane. The hybrid membrane with 4 wt% HAp/AC nanocomposite displayed 4.6 times higher pure water flux (~660 L/m2 h) than that of the pristine membrane (143 L/m2 h). In static adsorption experiments, it was found that the amount of humic acid (HA) and bovine serum albumin (BSA) adsorbed by the HAp/AC-PES hybrid membrane was much lower than that of the original membrane due to the electrostatic repulsive forces between them and the surface of the membrane. Irreversible fouling was reduced from 33 to 6 % for HA and from 46 to 8 % for BSA after HAp/AC was incorporated into the PES matrix. After 7 cycles of water-BSA-water, the HAp/AC-PES hybrid membrane maintained a high pure water flux of 540 L/m2 h with an excellent flux recovery ratio (FRR), demonstrating the long-term stability of the membranes. The developed UF membranes outperformed the original PES membranes in terms of permeability, selectivity, and antifouling.

Polyaniline-Pectin nanoparticles immobilized paper based colorimetric sensor for detection of Escherichia coli in milk and milk products.

In the food quality and safety arena, there is a need to develop novel and sustainable methodologies that can help in the prevention of foodborne diseases. Herein, we report the development of a rapid conducting polymer strip-based sensor using Polyaniline-pectin (PANI-PEC) for the detection of Escherichia coli in milk and milk products. Polyaniline-pectin nanoparticles stabilized with biopolymer pectin were synthesized and its characterization studies such as FTIR, UV-Vis spectroscopy, electrical conductivity and particle size analysis were done. The assay parameters were optimized for the selective detection of E. coli in milk and milk products. The concentration of PANI-PEC solution immobilized/strip was optimized to be 3 mg/mL as it exhibited good sensitivity and colour intensity. Based on acid production and selectivity for E.coli, concentrations of media components like lactose, tryptophan, yeast extract, chondroitin sulphate, sodium lauryl sulphate, potassium chloride, tergitol-7, gentamycin sulphate and ampicillin trihydrate were optimized as 0.9, 0.1, 0.45, 0.015, 0.1, 2, 0.0125, 0.00016 and 0.015 respectively and sample volume was optimized to 500 µL. The developed PANI-PEC colorimetric strip-based sensor detects 0.52 ± 0.17 log CFU/mL E. coli within 10: 21 h (h). Further shelf-life study revealed that the developed PANI-PEC colorimetric sensor strips are stable at room temperature up to six months exhibiting the same sensitivity. The results obtained here indicate that this novel and simple paper based colorimetric sensor holds potential for application in food industries as a reliable and rapid method for detection of E. coli in milk and milk products at various stages of production and processing.

Fabrication of Ru-CoFe2O4/RGO hierarchical nanostructures for high-performance photoelectrodes to reduce hazards Cr(VI) into Cr(III) coupled with anodic oxidation of phenols.

Dual-functional photo (electro)catalysis (PEC) is a key strategy for removing coexisting heavy metals and phenolic compounds from wastewater treatment systems. To design a PEC cell, it is crucial to use chemically stable and cost-effective bifunctional photocatalysts. The present study shows that ruthenium metallic nanoparticles decorated with CoFe2O4/RGO (Ru-CoFe2O4/RGO) are effective bifunctional photoelectrodes for the reduction of Cr(VI) ions. Ru-CoFe2O4/RGO achieves a maximum Cr(VI) reduction rate of 99% at 30 min under visible light irradiation, which is much higher than previously reported catalysts. Moreover, PEC Cr(VI) reduction rate is also tuned by adding varying concentration of phenol. A mechanism for the concurrent removal of Cr(VI) and phenol has been revealed over a bifunctional Ru-CoFe2O4/RGO catalyst. A number of key conclusions emerged from this study, demonstrating the dual role of phenol during Cr(VI) reduction by PEC. Anodic oxidation of phenol produces the enormous H+ ion, which appears to be a key component of Cr(VI) reduction. Additionally, phenolic molecules serve as hole (h+) scavengers that reduce e-/h+ recombination, thus enhancing the reduction rate of Cr(VI). Therefore, the Ru-CoFe2O4/RGO photoelectrode exhibits a promising capability of reducing both heavy metals and phenolic compounds simultaneously in wastewater.

Adsorptive removal of Acid Blue 113 using hydroxyapatite nanoadsorbents synthesized using Peltophorum pterocarpum pod extract.

The present work reports the study on the green synthesis of hydroxyapatite (HAP) nanoadsorbents using Peltophorum pterocarpum pod extract. HAP nanoadsorbents were characterized by using FESEM, EDS, TEM, XRD, FTIR, XPS, and BET analyses. The results highlighted the high purity, needle-like aggregations, and crystalline nature of the prepared HAP nanoadsorbents. The surface area was determined as 40.04 m2/g possessing mesopores that can be related to the high adsorption efficiency of the HAP for the removal of a toxic dye, - Acid Blue 113 (AB 113) from water. Central Composite Design (CCD) was used for optimizing the adsorption process, which yielded 94.59% removal efficiency at the optimum conditions (dose: 0.5 g/L, AB 113 dye concentration: 25 ppm, agitation speed: 173 rpm, and adsorption time: 120 min). The adsorption kinetics followed the pseudo-second-order model (R2:0.9996) and the equilibrium data fitted well with the Freundlich isotherm (R2:0.9924). The thermodynamic parameters indicated that the adsorption of AB 113 was a spontaneous and exothermic process. The highest adsorption capacity was determined as 153.85 mg/g, which suggested the promising role of green HAP nanoadsorbents in environmental remediation applications.

High-Grade Biofuel Synthesis from Paired Electrohydrogenation and Electrooxidation of Furfural Using Symmetric Ru/Reduced Graphene Oxide Electrodes.

Electrochemical hydrogenation is a challenging technoeconomic process for sustainable liquid fuel production from biomass-derived compounds. In general, half-cell hydrogenation is paired with water oxidation to generate the low economic value of O2 at the anode. Herein, a new strategy for the rational design of Ru/reduced graphene oxide (Ru/RGO) nanocomposites through a cost-effective and straightforward microwave irradiation technique is reported for the first time. The Ru nanoparticles with an average size of 3.5 nm are well anchored into the RGO frameworks with attractive nanostructures to enhance the furfural's paired electrohydrogenation (ECH) and electrooxidation (ECO) process to achieve high-grade biofuel. Furfural is used as a reactant with the paired electrolyzer to produce furfuryl alcohol and 2-methylfuran at the cathode side. Simultaneously, 2-furic acid and 5-hydroxyfuroic acid along with plenty of H+ and e- are generated at the anode side. Most impressively, the paired electrolyzer induces an extraordinary ECH and ECO of furfural, with the desired production of 2-methylfuran (yield = 91% and faradic efficiency (FE) of 95%) at XFF = 97%, outperforming the ECH half-cell reaction. The mechanisms of the half-cell reaction and paired cell reaction are discussed. Exquisite control of the reaction parameters, optimized strategies, and the yield of individual products are demonstrated. These results show that the Ru/RuO nanocomposite is a potential candidate for biofuel production in industrial sectors.

Green synthesis of zinc oxide nanoparticles using Phoenix dactylifera waste as bioreductant for effective dye degradation and antibacterial performance in wastewater treatment.

Production of multi-functional zinc oxide nanoparticles (ZnO-NPs) for wastewater treatment through green-approaches is a desirable alternative for conventional synthesis routes. Biomass waste valorization for nanoparticles synthesis has received increased research attention. The present study reports date pulp waste (DPW) utilization as an effective bio-reductant for green-synthesis of ZnO-NPs. A simple and eco-friendly process with low reaction time and calcination temperature was adopted for DPW mediated ZnO-NPs (DP-ZnO-NPs) synthesis. Microscopic investigations of DP-ZnO-NPs confirmed the non-agglomeration and spherical nature of particles with mean diameter of 30 nm. EDX and XPS analysis defined the chemical composition and product purity of DP-ZnO-NPs. UV and photoluminescence studies exhibited surface plasmonic resonance at 381 nm and fluorescent nature of DP-ZnO-NPs. FTIR studies established a formation mechanism outline for DP-ZnO-NPs. XRD and Raman investigations confirmed the crystalline and hexagonal wurtzite phase of DP-ZnO-NPs. DSC/TG analysis displayed the thermal stability of DP-ZnO-NPs with <10 wt% loss upto 700 °C. Photocatalytic degradation of hazardous methylene blue and eosin yellow dyes using DP-ZnO-NPs, showed rapid decomposition rate with 90 % degradation efficiency. Additionally, DP-ZnO-NPs demonstrated significant antibacterial effects on various pathogenic bacteria in terms of zone-of-inhibition measured by disc-diffusion method. Thus, the as-prepared DP-ZnO-NPs is suitable for industrial wastewater treatment.

Improved permeability and antifouling performance of polyethersulfone ultrafiltration membranes tailored by hydroxyapatite/boron nitride nanocomposites.

To extend the use of polyethersulfone (PES) ultrafiltration membranes in water process engineering, the membrane's wettability and anti-fouling properties should be further improved. In this context, hydroxyapatite/boron nitride (HAp/BN) nanocomposites have been prepared and intercalated into PES membranes using a non-solvent-induced phase separation process. High-quality 2D transparent boron nitride nanosheets (BN NSs) were prepared using an environmentally friendly and green-template assisted synthesis method in which 1D hexagonal hydroxyapatite nanosheets (HAp NRs) were uniformly distributed and hydrothermally immobilized at 180 °C. SEM, XRD, and Raman spectroscopy techniques were used to characterize the HAp/BN nanocomposites. PES membranes intercalated with various nanocomposite amounts (0-4 wt %) were also characterized by permeability, porosity, and contact angle measurements. Additional pathways for water molecule transport were promoted by the high surface area of the BN NSs, resulting in high permeability. Membrane wettability and antifouling properties were also improved by the inclusion of negative charge groups (OH- and PO43-) on HAp. Hybrid membranes containing 4 wt% HAp/BN showed the best overall performance with ∼97% increase in water flux, 90% rejection of bovine serum albumin (BSA), high water flux recovery ratio, low irreversible fouling, and high reversible fouling pattern. The intercalation of HAp/BN with the PES matrix therefore opens up a new direction to enhance the PES UF membranes' hydrophilicity, water flux, and antifouling capacity.

Nano-activated carbon derived from date palm coir waste for efficient sequestration of noxious 2,4-dichlorophenoxyacetic acid herbicide.

Alarming water contamination rates by toxic herbicides have drawn attention to treat these pollutants using efficient, easy, and economic techniques. In this work, date-palm coir (DPC) waste-based nano-activated carbon (DPC-AC) was successfully prepared and examined for adsorptive removal of toxic 2,4-dichlorophenoxyacetic acid (2,4-DPA) herbicide from synthetic wastewater. The DPC-AC was synthesized via a single-step carbonization-KOH activation approach. The nanosorbent displayed a flaky morphology with graphitic structure and oxygen-rich surface functionalities. The nanocarbon with a mean particle size of 163 nm possessed a high specific surface area of 947 m2/g with an average pore size of 2.28 nm. High 2,4-DPA removal efficiency of 98.6% was obtained for the optimal adsorption conditions of pH 2, dosage 0.15 g, rotational speed 100 rpm, time 90 min, and initial 2,4-DPA concentration of 100 mg/L. Langmuir isotherm best described the equilibrium behavior with a theoretical maximum of 50.25 mg/g adsorption capacity for the system. Pseudo-second order model was more appropriate in quantifying the kinetics for all initial feed concentrations. Thermodynamically, the adsorption process was spontaneous, endothermic, and involved low activation energy. A plausible mechanism for the adsorption-desorption of 2,4-DPA onto DPC-AC is also discussed. Cost analysis and regenerability studies proved the economic value ($3/kg) and reusable nature of DPC-AC without any significant loss in its performance. Overall, this study highlights the advantages of DPC waste valorization into efficient nanoadsorbent and the sequestration of noxious 2,4-DPA herbicide from its aqueous streams using this nanosorbent.

Development of chitosan/poly (vinyl alcohol)/graphene oxide loaded with vanadium doped titanium dioxide patch for visible light driven antibacterial activity and accelerated wound healing application.

Wound healing is a multi-stage process that is dynamic, interactive, and complicated. However, many nanomaterials are employed to expedite wound healing by demonstrating antibacterial activity or boosting cell proliferation. But only one phase is focused during the wound healing process. As a result, there is a need for optimum wound dressing materials that promotes different wound healing cascades with ideal properties. Herein, Graphene Oxide loaded with vanadium (V) doped titanium dioxide (TiO2) blended with chitosan, and polyvinyl alcohol (CS/PVA/GO/TiO2-V) patch was developed for wound healing. XRD, FTIR and FE-SEM analyses were carried out to study the morphology and structural property of the patch. The fabricated patch has a high surface porosity, excellent moisture vapor transfer rate, appropriate swelling behaviour, and oxygen permeability, which results in an excellent moist environment for wound breathing and effective management of wound exudates. The antibacterial test showed significant antibacterial efficacy against wound infections in the presence of light when compared to dark. In-vitro analysis such as hemocompatibility, cytotoxicity, cell adhesion, and scratch assay show the predicted potential wound healing application with high biocompatibility. These results suggest that CS/PVA/GO/TiO2-V patch provides a microenvironment favourable to cells' growth and differentiation and positively modulates full-thickness wounds' healing.

Augmented biohydrogen production from rice mill wastewater through nano-metal oxides assisted dark fermentation.

This study highlights biohydrogen production enrichment through NiO and CoO nanoparticles (NPs) inclusion to dark fermentation of rice mill wastewater using Clostridium beijerinckii DSM 791. NiO (~26 nm) and CoO (~50 nm) NPs were intrinsically prepared via facile hydrothermal method with polyhedral morphology and high purity. Dosage dependency studies revealed the maximum biohydrogen production characteristics for 1.5 mg/L concentration of both NPs. Biohydrogen yield was improved by 2.09 and 1.9 folds higher for optimum dosage of NiO and CoO respectively, compared to control run without NPs. Co-metabolites analysis confirmed the biohydrogen production through acetate and butyrate pathways. Maximum COD reduction efficiencies of 77.6% and 69.5% were observed for NiO and CoO inclusions respectively, which were higher than control run (57.5%). Gompertz kinetic model fitted well with experimental data of NPs assisted fermentation. Thus, NiO and CoO inclusions to wastewater fermentation seems to be a promising technique for augmented biohydrogen production.

Biosorption potential of Phoenix dactylifera coir wastes for toxic hexavalent chromium sequestration.

Valorization of waste phytomass into valuable components provide new functionality to these biowastes and annul problems associated with their safe disposal. In this study, date palm (Phoenix dactylifera) coir (DPC) waste was tested for its toxic hexavalent chromium (Cr(VI)) ions biosorption. The DPC biosorbent was subjected to SEM, EDX, FTIR, TGA and N2 adsorption/desorption characterization studies. Results showed that the cellulose-rich DPC surface contained mesopores with a wide number of functional groups and possessed suitable surface attributes for Cr(VI) ions sequestration. Batch biosorption tests established the Cr(VI) ions sequestration potential of the DPC biosorbent with a maximum chromium removal efficiency of 87.2% for a 100 ppm initial feed concentration at pH 2, dosage 0.3 g, temperature 30 °C, contact time 60 min and agitation speed 100 rpm. Langmuir isotherm fitted well (R2 = 0.9955) with the experimental data while the kinetic analysis showed that Cr(VI) ions sequestration by DPC followed the pseudo-second order model. Biosorption thermodynamics revealed the exothermic nature and low-temperature preference for the effective binding of chromium ions on DPC. Regeneration of the biosorbent using NaOH wash showed a nearly steady Cr(VI) ions removal efficiency (with a loss <10%) by the DPC till four recycle runs. Economic analysis showed a very low production cost of $1.09/kg for the DPC biosorbent with a total cost of $4.36/m3 for a scale-up batch process wastewater treatment plant. Thus, a low-cost, effectual and sustainable biosorbent for effective treatment of Cr(VI) ions polluted water streams has been reported.