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Lignocellulosic biomass can uptake CO2 during growth, which can then be pyrolysed into three major products, biochar (BC), syngas, and bio-oil. Due to the presence of oxygenated organic compounds, the produced bio-oil is not suitable for direct use as a fuel and requires upgrading via hydrodeoxygenation (HDO) and hydrogenation. This is typically carried out over a supported metal catalyst. Regarding circular economy and sustainability, the BC from the pyrolysis step can potentially be activated and used as a novel catalyst support, as reported here. A 15 wt% Ni/BC catalyst was developed by chemically modifying BC with sulfuric acid to improve mesoporous structure and surface area. When compared to the pristine Ni/BC catalyst, sulfuric activated Ni/BC catalyst has excellent mesopores and a high surface area, which increases the dispersion of Ni nanoparticles and hence improves the adsorptive effect and thus catalytic performance. A liquid phase hydrogenation of furfural to 2-methylfuran was performed over the developed 15 wt% Ni/BC catalyst. Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic type models for adsorption of dissociative H2 were screened based on an R2 value greater than 99%, demonstrating that the experimental data satisfactorily fit to three plausible models: competitive (Model I), competitive at only one type of adsorption site (Model II), and non-competitive with two types of adsorption sites (Model III). With a correlation coefficient greater than 99% between the experimental rates and the predicted rate, Model III, which is a dual-site adsorption mechanism involving furfural adsorption and hydrogen dissociative adsorption and surface reaction, is the best fit. The Ni/BC catalyst demonstrated comparative performance and significant cost savings over previous catalysts; a value of 24.39 kJ mol−1 was estimated for activation energy, −11.43 kJ mol−1 for the enthalpy of adsorption for H2, and −5.86 kJ mol−1 for furfural. The developed Ni/BC catalyst demonstrated excellent stability in terms of conversion of furfural (96%) and yield of 2-methylfuran (54%) at the fourth successive experiments. Based on furfural conversion and yield of products, it appears that pores are constructed slowly during sulfuric acid activation of the biochar. [ABSTRACT FROM AUTHOR]

A series of surface-enhanced resonance Raman scattering (SERRS) based probes for the detection of lipase activity are reported. A number of novel SERRS-active 8-hydroxylquinolinyl azo dyes have been prepared and via synthetic esterification or subsequent enzymatic hydrolysis at the 8-hydroxyl position the SERRS signal can be 'switched' on or off. In the first instance, the technique has been demonstrated for the successful detection of lipase from Pseudomonas cepaeia, and these new compounds offer a limit of detection of 0.2 ng [mL.sup.-1] enzyme, up to a 100-fold lower limit than observed for benzotriazolyl dyes used in previous studies. The chemical synthesis is straightforward and allows for facile introduction of a wide range of different masking groups, using commonly known synthetic methodologies. The potential for multiplexing analysis of enzyme activity using this technology is presented within.

Gas adsorption is widely used in air pollution control, with mainly activated carbon and zeolites used as adsorbents. Although physical and chemisorption can be used, most air pollution applications involve physical adsorption, now also increasingly investigated for CO2 abatement from combustion gas. Empirical adsorption treatments have been presented since many decades, but solely rely on the comparison of adsorbate feed and exhaust concentrations of the adsorption bed. In-situ measurements, to study the absorbate/adsorbent interactions in real time, are compared in the present review when performed by a three-dimensional (3D) Positron Emission Tomography of an adsorbing 11CO2 radioactive tracer on activated carbon versus a zeolite adsorbent. The overall results are validated by conventional exit gas analysis. Results are defining both the time-dependent adsorption parameters, such as the progressing adsorption front and Mass Transfer Zone along the adsorbent bed length, and enable to assess previous semi-empirical adsorption correlations toward their optimum validity in predicting adsorption isotherms, kinetics and mechanisms. [ABSTRACT FROM AUTHOR]