Differential tolerance of Trichoderma harzianum and Rhizoctonia solani towards silver nanoparticles: potential for agricultural applications?

In the previous study, we examined the effect of silver nanoparticles (AgNPs) on beneficial soil fungus including Trichoderma harzianum (T22), and pathogenic soil-borne fungus, Rhizoctonia solani (AG3-PT). The result exhibited that T. harzianum (T22) is tolerance towards AgNPs. On the other hand, the pathogenic fungi, R.solani (AG3-PT), is more sensitive to AgNPs. T. harzianum is well known as biocontrol agent to suppress R. solani. Therefore, in this study we investigated the combination of T. harzianum (T22) and AgNPs at low concentration to control two strains of R. solani (AG3-PT and AG2-1). The effect of AgNPs at two different levels (20 mg L-1 and 50 mg L-1) was examined over the growth of the two strains of R. solani and T. harzianum (T22) using dual culture technique. The results shows that this combination have a potential to reduce colony growth of R. solani (AG2-1) at higher AgNPs concentration. However, it was not the case for R. solani (AG3-PT). It can be concluded that AgNPs toxicity depend on several factors including species strain and the size of AgNPs particle

Screen-printed stretchable supercapacitors based on tin sulfide-decorated face-mask-derived activated carbon electrodes with high areal energy density

In this work, tin sulfide nanosheets decorated on face-mask-derived activated carbon have been explored as electrode material for electrochemical supercapacitors. A hydrothermal route was employed to grow tin sulfide on the surface and inside of high-surface-area face-mask-derived activated carbon, activated at 850 °C, to produce a hierarchical interconnected porous composite (ACFM-850/TS) structure. The presence of tin sulfide in the porous carbon framework exposed the surface active sites for rapid adsorption/desorption of electrolyte ions and ensured high utilization of the porous carbon surface. Furthermore, the porous ACFM-850 framework prevented the stacking/agglomeration of tin sulfide sheets, thereby enhancing the charge-transport kinetics in the composite electrodes. Benefiting from the synergistic effect of tin sulfide and ACFM-850, the resulting ACFM-850/TS composite exhibited an attractive specific capacitance of 423 F g–1 at a 0.5 A g–1 current density and superior rate capability (71.3% at a 30 A g–1 current density) in a 1.0 M Na2SO4 electrolyte. In addition, we fabricated a planar symmetric interdigitated supercapacitor on a stretchable Spandex fabric using an ACFM-850/TS composite electrode and carboxymethyl cellulose/NaClO4 as a solid-state gel electrolyte employing a scalable screen-printing process. The as-prepared stretchable supercapacitors displayed an ultrahigh energy density of 9.2 μWh cm–2 at a power density of 0.13 mW cm–2. In addition, they exhibited an excellent cyclic stability of 64% even after 10,000 charge–discharge cycles and 42% after 1000 continuous stretch (at 25% stretching)/release cycles. Such screen-printed interdigitated planar supercapacitors with activated carbon composite electrodes and a solid-state gel electrolyte act as promising low-cost energy-storage devices for wearable and flexible integrated electronic devices

Diamond-doped silica aerogel for solar geoengineering

Even though aerosol injection into stratosphere is one of the most promising solar geoengineering techniques, sulfate aerosols, which are suggested for such an application, show significant drawbacks such as infra-red (IR) absorption and ozone degradation. The development of new materials for such application that would exhibit substantial up-scattering, with non-IR absorption to allow a cooling effect are needed. Here, a novel composite material comprised of diamonds dispersed in a silica aerogel network is investigated and compared to pure silica aerogel. Silica aerogels are ultralight, highly porous, transparent and can host particles, while fulfilling particle size limitation in terms of potential health risks for humans during respiration. Morphology of both the diamonds and the silica aerogels composites has been studied. The diffuse reflectance of the diamond powders, pure silica aerogels, and the diamond-doped silica aerogels have been measured for comparison. Our experimental work assesses the proposed concept of materials, including discussion and recommendations for the improvements of the synthetized materials. The obtained results are promising and could stimulate further in-depth studies in similar materials with a potential for applications in solar geoengineering

Nickel Nanoparticles for Enhancing Carbon Capture

Hydration reaction of CO2 is one of the rate limiting steps for CO2 absorption (in aqueous solutions) and aqueous CO2 mineralization. The catalytic activity of nickel nanoparticles (NiNPs) for CO2 hydration is studied at different temperatures, pH, and low CO2 partial pressures to mimic the true flue gas conditions. Results show that NiNPs can work as active catalyst for hydration of CO2 in applications such as CO2 separation and CO2 mineralization. The NiNPs display optimum activity within 20–30°C and at pH value <8. NiNPs show catalytic activity even at low CO2 partial pressures (12 vol%). In 50 wt% K2CO3 solution, an enhancement of 77% is observed in the rate of CO2 absorption with NiNPs. Commercially, CO2 saturated K2CO3 solutions are usually regenerated at 150°C; at these conditions, NiNPs show no considerable surface oxidation. They still exhibit catalytic activity for hydration reaction of CO2. CO2 absorption and mineralization (as CaCO3) in DI water are three times higher in presence of NiNPs. Calcite (CaCO3) particles precipitated in presence of NiNPs are spherical in morphology

Effect of sodium bicarbonate solution on methyltrimethoxysilane-derived silica aerogels dried at ambient pressure

Here we present an economical ambient pressure drying method of preparing monolithic silica aerogels from methyltrimethoxysilane precursor while using sodium bicarbonate solution as the exchanging solvent. We prepared silica aerogels with a density and a specific surface area of 0.053 g·cm−3 and 423 m2·g−1, respectively. The average pore diameter of silica aerogels is 23 nm as the pore specific volume is 1.11 cm3·g−1. Further, the contact angle between water droplet and the surface of silica aerogels in specific condition can be as high as 166°, which indicates a super-hydrophobic surface of aerogels

Scottish softwood biochar for water remediation targeting selected persistent organic pollutants

A Scottish wood biochar sample was investigated for water remediation against persistent organic pollutants as a potential renewable material for adsorption processes. Textural characterisation gave a high surface area (588 m2/g) and a mix of microporous and mesoporous nature with an average pore width of 4 nm. Morphological analysis revealed a layered carbon structure and spectroscopic analysis showed the presence of oxygen and nitrogen-based functionalities alongside 80% atomic carbon. The biochar had an average point of zero charge of 7.44±0.2. 3,4-Dichloroaniline kinetic rates were rapid (<5 min), restricting kinetic analysis, while a pseudo second order kinetic model was best suited to represent the kinetic data for acetaminophen and carbamazepine, suggesting chemical control. The adsorption equilibria were most appropriately described by the Sips isotherm model, further supporting the chemical control theory for a multilayer system. Maximum adsorption capacity was 126 mg/g for acetaminophen removal, 40 mg/g for carbamazepine and 83 mg/g for 3,4-dichloroaniline. The biochar demonstrated good removal efficiency against all target species, showing potential as an adsorbent for water remediation

Cyclic production of biocompatible few-layer graphene ink with in-line shear-mixing for inkjet-printed electrodes and Li-ion energy storage

The scalable production of two-dimensional (2D) materials is needed to accelerate their adoption to industry. In this work, we present a low-cost in-line and enclosed process of exfoliation based on high-shear mixing to create aqueous dispersions of few-layer graphene, on a large scale with a Yw ~ 100% yield by weight and throughput of ϕ ~ 8.3 g h−1. The in-line process minimises basal plane defects compared to traditional beaker-based shear mixing which we attribute to a reduced Reynolds number, Re ~ 105. We demonstrate highly conductive graphene material with conductivities as high as σ ∼ 1.5 × 104 S m−1 leading to sheet-resistances as low as Rs ∼ 2.6 Ω □−1 (t ∼ 25 μm). The process is ideal for formulating non-toxic, biocompatible and highly concentrated (c ∼ 100 mg ml−1) inks. We utilise the graphene inks for inkjet printable conductive interconnects and lithium-ion battery anode composites that demonstrate a low-rate lithium storage capability of 370 mAh g−1, close to the theoretical capacity of graphite. Finally, we demonstrate the biocompatibility of the graphene inks with human colon cells and human umbilical vein endothelial cells at high c ∼ 1 mg ml−1 facilitating a route for the use of the graphene inks in applications that require biocompatibility at high c such as electronic textiles.publishedVersio

Efficient hydrolytic hydrogen evolution from sodium borohydride catalyzed by polymer immobilized ionic liquid‐stabilized platinum nanoparticles

Platinum nanoparticles stabilized by imidazolium‐based phosphine‐decorated Polymer Immobilized Ionic Liquids (PPh2‐PIIL) catalyze the hydrolytic evolution of hydrogen from sodium borohydride with remarkable efficiency, under mild conditions. The composition of the polymer influences efficiency with the catalyst based on a polyethylene glycol modified imidazolium monomer (PtNP@PPh2‐PEGPIILS) more active than its N‐alkylated counterpart (PtNP@PPh2‐N‐decylPIILS). The maximum initial TOF of 169 moleH2.molcat−1.min−1 obtained at 30 °C with a catalyst loading of 0.08 mol% is among the highest to be reported for the aqueous phase hydrolysis of sodium borohydride catalyzed by a PtNP‐based system. Kinetic studies revealed that the apparent activation energy (Ea) of 23.9 kJ mol−1 for the hydrolysis of NaBH4 catalyzed by PtNP@PPh2‐PEGPIILS is significantly lower than that of 35.6 kJ mol−1 for PtNP@PPh2‐N‐decylPIILS. Primary kinetic isotope effects kH/kD of 1.8 and 2.1 obtained with PtNP@PPh2‐PEGPIILS and PtNP@PPh2‐N‐decylPIILS, respectively, for the hydrolysis with D2O support a mechanism involving rate determining oxidative addition or σ‐bond metathesis of the O−H bond. Catalyst stability and reuse studies showed that PtNP@PPh2‐PEGPIILS retained 70 % of its activity across five runs; the gradual drop in conversion appears to be due to poisoning of the catalyst by the accumulated metaborate product as well as the increased viscosity of the reaction mixture

Corn husk derived activated carbon/siloxene composite electrodes based symmetric supercapacitor with high Energy density and wide temperature tolerance

In the present work, novel composite material comprising of corn husk derived activated carbon and siloxene nanosheets have been explored as new class of multicomponent electrode material for fabricating high energy density supercapacitors with wide temperature tolerance. The activated carbon obtained from corn husk (ACH−900) with high surface area and pore volume acts as an ideal framework for hosting siloxene nanosheets (S) that allows the overall siloxene−corn husk derived activated carbon (ACH−900/S) composite to deliver excellent electrochemical performance. The as-prepared ACH−900/S composite electrode exhibited a high specific capacitance of 415 F g−1 at 0.25 A g−1 and retained 73.4% of its initial capacitance even at a high current density of 30 A g−1 in 1 M Na2SO4 electrolyte. In addition, the symmetric supercapacitor assembled with “acetonitrile/water-in-salt (AWIS)” electrolyte exhibited an energy density of 57.2 W h kg−1 at 338 W kg−1 with a cyclic stability of 92.8% after 10000 cycles at 5 A g−1 current density. Besides, the fabricated ACH−900/S supercapacitor can operate over wide temperature range from 0 to 100 °C. This work opens up new frontiers to develop low-cost safe supercapacitors with wide temperature tolerance and excellent electrochemical performance