The size distribution and morphology of silicon nanoparticles have been studied using small‐angle X‐ray scattering (SAXS) and transmission electron microscopy. Quantitative agreement was established between the results of the two methods. The surface characteristics, as well as the size distribution, were found to be independent of the choice of binder material used to prepare printed layers containing the nanoparticles. Intrinsic silicon nanoparticles, produced by laser pyrolysis of silane, have been shown to have a narrow, effectively monodisperse, size distribution and to be roughly spherical in shape. SAXS measurements indicate that the particles have a regular geometry and a smooth surface. There is, however, a thin disordered region at the surface of the particles. Particles produced by milling of bulk silicon have surface fractal characteristics and a high dispersivity resulting from the milling process, in which the particles become smoother as they are milled to smaller size or for longer periods. The size dispersion, but not the median size, is similarly reduced by milling for longer periods

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The decolorization of congo red (CR) in aqueous solution is investigated in a batch mode using termite mound as an adsorbent. Elemental analysis and identification of the mineral composition/phases in the termite mound sample is carried out by means of X‐ray fluorescence and X‐ray diffraction. The optimal percentage removal and equilibrium adsorption capacity of CR by the termite mound achieved is found to be 95.68% and 2.30 mg g−1, respectively, when 0.5 g of termite mound is added to 30 mL of 40 mg L−1 CR for 60 min−1 at 400  rpm. The decolorization of CR increases with an increase in the termite mound dosage, contact time, stirring speed, pH, and temperature; however, the adsorption capacity decreases with an increase in the initial CR concentration. The adsorption process shows that CR obeys the Freundlich adsorption model with a 0.9355 coefficient of regression, denoting multilayer formation onto the termite mound. The adsorption kinetics follow the pseudo‐second‐order model with a coefficient of regression value of 0.9966, showing that chemisorption is the main rate limiting step. ΔG is negative, an indication that the adsorption of CR onto termite mound is spontaneous. Approximately 86.6% chemical oxygen demand reduction is achieved with real textile wastewater. This study shows how termite mound can be harnessed for the treatment of textile wastewater before discharged into the environment.

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