Phosphoric Acid-assisted Pretreatment Strategy for the Rational Synthesis of Lignin-derived Hierarchical Porous Carbon Toward High-performance Supercapacitors

In this article, a facile two-step activation method, coupled with phosphoric acid (H₃PO₄)-assisted pretreatment and followed KOH activation, was reported for constructing hierarchical porous carbon (HPC) materials derived from lignin. The introduction of H₃PO₄, cross-linked with lignin sources generated phosphate (and/or polyphosphate) ester groups throughout the lignin structure, which endowed the pre-activated intermediate char (IC) with a hierarchical porous structure. Such phosphate esters contributed to the multi-scale pore structure within the pre-activated IC, which was beneficial for the uniform distribution and impregnation of subsequent KOH activators, thus leading to the formation of HPC materials. The as-prepared HPC exhibited a large specific surface area (SSA) of 1345.1 m²/g, which ensures the accessibility of the ion diffusion pathways. The supercapacitors integrated with HPC delivered a high specific capacitance of 241 F/g (in a three-electrode system) and outstanding rate capability with an 80.9% capacitance retention from 0.5 A/g to an ultra-high current density of 50 A/g.     

Modification of Bentonite and Its Application in Antimicrobial Material

This paper aims to expand the application scope of bentonite. The structure of bentonite and the purification and pretreatment methods performed before its modification were reviewed. The modification of bentonite and its application in antibacterial materials were emphasized.     

Interactions between hybrid nanosized particles and convection melting inside an enclosure with partially active walls: 2D lattice Boltzmann-based numerical investigation

The ice melting is investigated inside a square cavity with two isothermally partially active walls. The concept of dispersing hybrid alumina–Cu nanoparticles and hybrid silica–multiwalled carbon nanotubes (MWCNTs) nanoparticles is recommended for thermal performance enhancement in this thermal energy storage (TES) system. The two-dimensional explicit lattice Boltzmann convection melting scheme in the single-phase model is applied to account for the natural convection flow induced in the melt region and evolution of the solid–liquid interface. The complete melting time for the pure phase change material (PCM) using case (II) is 33.3% lower compared with other cases. If the price of hybrid Al₂O₃–Cu nanoparticles and heat storage capacity is important, the full melt time diminishes by 16.6% with a volume fraction of 0.01 in case (II). Once hybrid silica–MWCNT nanoparticles with a volume fraction of 0.01 are utilized inside case (II), the lowest charging time is achieved. The complete melting time abates by 23.66% in contrast to the pure PCM melting. The use of single/hybrid nanoparticles to enhance the PCM melting is not necessarily economical as efficient positions of active parts could further lessen the charging time. The efficiency of hybrid nanoparticles is linked to the type and weight proportions of nanoparticles, and positions of thermally active parts.     

Study on effect of diverse air inlet arrangement on thermal management of cylindrical lithium-ion cells

Lithium-ion cells are preferred in the electrical powertrain due to high-power density, compactness, and modularity. In real driving conditions, the cells undergo discharge rates as high as 4 C resulting in high heat generation affecting the performance. To obtain the maximum performance the pack construction and thermal management of cells are crucial parameters. In our work, air-cooled technique with diverse air inlet and staggered scheme with a two-channel partition approach for thermal management of the cylindrical lithium-ion cells are studied in computational fluid dynamics. The simulation model is validated with experimental results. The obtained results demonstrate that the cells in the dual-directional air inlet arrangement had low maximum temperature difference among and within the cells and required least fan work. This arrangement required least fan work to generate optimal air inlet velocity of 2 m/s for 1, 2, and 3 C and 4 m/s for 4 C discharge rates. There is a reduction of 50% and 33% fan work for 3 and 4 C discharge rates, which are the majority operating points. Also, it shows that the temperature uniformity within the cells has improved. The results of this study can used to optimize parameters for designing an enhanced thermal management system.     

Radon in Private Water Supplies: The Unknown Risk

Radon gas, which is the main contributor to human radiation exposure, is easily dissolved in, and dissipated from, water. Problems with radon occur because, in addition to being ingested, it (a) becomes attached to particles which lodge in the lungs and (b) emits alpha radiation. Concentration has been found to increase inversely with the size of a water supply. Although of little problem in mains'water, private water supplies in the UK have been found to contain more than ten times the recommended US levels. Despite this, very little monitoring is carried out for radon in private supplies. Local authorities, situated in areas where the geological conditions are such that high levels of radon would be expected, should carry out a suitable sampling and monitoring programme of their private water supplies.     

Streambed Sediment as a Barrier to Groundwater Pollution: Insights from Fieldwork and Modelling in the River Thames Basin

Integrated fieldwork and modelling has been undertaken to assess the vulnerability of riverside wells to pollution when river water is contaminated. Results highlight the importance of streambed sediments as a barrier to groundwater pollution by river water. The bed of the River Thames is lined with brown and grey organic-rich silts of low hydraulic conductivity (about 0.002 m/d). A 3-D model for solute transport in stream-aquifer systems was developed and applied to two riverside sites in the middle Thames valley. Model results indicate that well-water quality would only breach EC limits if the river was heavily polluted for a week or even a month (clearly an unlikely scenario). Sensitivity analyses showed the models to be far more sensitive to streambed parameters than to aquifer parameters. Thus it would be more sensible to focus fieldwork on the measurement of streambed properties than on the more usually measured aquifer parameters.     

DERIVING UNIT HYDROGRAPHS FOR SMALL CATCHMENTS

An examination of 190 storm events in seventeen small Northern Ireland catchments, along lines developed by the UK Institute of Hydrology, shows that the time-to-peak of the instantaneous unit hydrograph can be estimated from catchment characteristics and from the time between the centroid of mass of a flood-producing rainfall event and of the resulting peak flow, but that equations calibrated on British data overestimate the time-to-peak. This might be due to the distinctive hydrology of Northern Ireland.     

Water and Wastewater Minimization: the Aire and Calder Project

The reduction of the waste of raw materials at source using clean technologies, recycling, and good housekeeping has considerable benefits for both the environment and industry. A demonstration project on wastewater minimization was completed in 1995 in the Aire and Calder catchments of West Yorkshire. The findings indicated cost savings for eleven firms of over $3 million/annum and further opportunities which, when implemented, could realize another $1 million/annum. The reduction in the amount of wastewater discharged either to sewer or river was 27%, with a potential to increase to over 40%. The payback period for 63% of the waste minimization opportunities is less than one year and many involve only a small initial investment. Waste minimization when widely adopted has prospects for cutting industry's costs, reducing demand for water and reducing the volume of effluent produced.