Removal efficiency of methylene blue (MEB) from aqueous media was studied under different experimental conditions of pH, contact time and initial concentration of the adsorbate. Activated rice husk biochar (ARHB) was characterized using BET surface area and XRD. The XRD diffraction indicated amorphous nature of the biochar with pore size (cc/g) and pore surface area (m2/g) of 9.369 and 27.32 respectively from BET surface area plot. Equilibrium isotherm based on coefficient of non-determination indicated the following order as best fit model: Hill ˃ Kiselev ˃Elovic ˃Flory-Huggins > Langmuir > Jovanovic > Harkin-Jura >Freundlich > Henry > Temkin >Redlich Peterson>Durbinin-Kaganer Redushkevich >Hill-de Boer > Fowler-Guggenheim. Based on the highest correlation coefficient and the lowest values of the error functions applied to the kinetic models, Weber and Morris intra-particle diffusion and liquid film diffusion were noted to be in control of the sorption rate. The MEB sorption capacity of the activated biochar was 356.99 mmolkg-1 which was in the range of commercially available activated carbons and other biosorbents.

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AbstractThis work involved the production and thermal characterization of biomass briquettes produced by blending a major agricultural waste with coal dust. In the work, nine different compositions of coal dust/groundnut husk briquettes were produced using starch as the binder while Ca(OH2) was incorporated as the de-sulphurizing agent. The ash content, volatile matter, fixed carbon, moisture content, compressive strength, ignition time, calorific value, water boiling test and burning rate were carried out to determine the physical, mechanical and thermal properties of the briquettes produced. The results showed that moisture content values are in the range 2.43 - 6.44%, for compressive strength 7.72 - 10.85 N/mm3, for ash content 24.18 - 29.15 %, for calorific value 21714.17 - 25027.18 kJ/kg, for fixed carbon 16.77-53.22 %, for ignition time 22.23-45.20 s, for water boiling test 1.50-4.99 min and burning rate 16.10-28.32 g/min. These are appreciable values for the thermal properties of the bio-briquettes. Therefore, the agro-wastes briquettes are beneficial for heating purposes rather than open incineration of the wastes.

Coordination polymers including metal-organic frameworks, clathrates and cyanometallates have recently gained significance as an important class of solid state materials. In this critical review, the diversity, classification, synthesis, structure, properties, applications, geometrical and chemical factors that influence their formation have been carefully presented. The synthesis of these new classes of compounds from molecular building blocks and demonstration of their high surface area, adsorptive and trapping potentials of molecules, selectivity in separation and uptake of molecules, tunable and modifiable molecular structure, and photoluminescence, magnetic and antimicrobial responses holds the potential for innumerable applications based on these tailored properties.

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