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The present work attempts to convert bamboo into a high surface area activated carbon via microwave heating. Different chemical activating agents such as KOH, NaOH, K2CO3 and Na2CO3 were utilized to identify a most suitable activating agent. Among the activating agents tested KOH was found to generate carbon with the highest porosity and surface area. The effect of KOH/C ratio on the porous nature of the activated carbon has been assessed. An optimal KOH/C ratio of 4 was identified, beyond which the surface area as well as the pore volume were found to decrease. At the optimized KOH/C ratio the surface area and the pore volume were estimated to be 3,441 m2/g and 2.093 ml/g, respectively, with the significant proportion of which being microporous (62.3%). Activated carbon prepared under the optimum conditions was further characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Activated carbons with so high surface area and pore volume are very rarely reported, which could be owed to the nature of the precursor and the optimal conditions of mixture ratio adopted in the present work.

Eupatorium adenophorum was utilized as raw materials for the preparation of activated carbon via microwave assisted steam activation. Influences of the three vital process parameters – activation temperature, activation duration and steam flow rate – have been assessed on the adsorption capacity and yield of Eupatorium adenophorum activated carbon (EAAC). The process parameters were optimized utilizing the Design Expert software and were identified to be an activation duration of 45 min, an activation temperature of 950 °C and a steam flow rate of 0.7 ml/min, with the resultant iodine number and yield being 1,010 mg/g and 20.13% respectively. The validity of process model to optimize the process parameters was verified using the analysis of variance (ANOVA). The key parameters that characterize quality of the porous carbon such as the BET surface area, total pore volume and average pore diameter were estimated to be 1,142 m2/g, 0.84 ml/g and 3.3 nm respectively, for the sample corresponding to the optimized process conditions. Additionally the pore structure is characterized using Scanning Electron Microscope (SEM). The present work strongly supports utilization of Eupatorium adenophorum as a potential precursor through microwave heating.

The kinetics of carbothermic reduction of ZnFe2O4 in the temperature range 823–1223 K, was investigated in a microwave reactor. The mechanism of formation of ZnO and Fe3O4/FeO by decomposition of ZnFe2O4 was explained using the equilibrium calculations and thermodynamics analysis using HSC chemistry software 6.0. In addition the effect of parameters such as the decomposition temperature, C/ZnFe2O4 ratio, particle size and microwave power were assessed on the decomposition kinetics. Zn recovery as high as 98.83% could be achieved at a decomposition temperature of 1023 K, C/ZnFe2O4 ratio of 1:3, particle size of +74–61 µm and microwave power of 1200 W. The kinetics of decomposition was found to be carbon gasification reaction controlled, with the activation energy of 39.21 kJ/mol.

Microwave and conventional heating were employed to synthesize micro-sized hematite powder from hydrous ferrous sulfate, a by-product in the process of titanium pigment manufacture. The TG/DTG analysis was used to study thermal behavior of the industrial ferrous sulfate. Therefore the temperature which was significant to product was defined. The calcination experiments were carried out to assess the effect of calcination temperature covering three different temperatures (650°C, 750°C and 850°C, respectively). X-ray powder diffraction (XRD) was used to characterize the structure of the product, while the scanning electron microscopy (SEM) was utilized to characterize the morphology of the product. Microwave calcination process resulted in a mixture of hematite and minor magnetite while a considerable amount of magnesium sulfate was detected with the conventional calcination process. The transformation from periclase to magnesium was discussed during the calcinations as well. The conventional heating resulted in porous product while the microwave heating resulted in smaller particle size.

BaCO3 nanoparticles with different morphologies including needle-like, rod-like, bird's nest-like and flower-like have been successfully synthesized by the microwave homogeneous precipitation method using BaCl2·2H2O, NaOH and (NH2)2CO as raw materials with the help of different guide reagents, such as citric acid (CA), sodium triphosphate (STPP) and ethylene diamine tetraacetic acid (EDTA). Their phases and morphologies were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM), respectively. The characterization results show that different guide reagents have little effect on the phase structure and composition of products while they play significant roles in determining the morphology of products. All the synthesized BaCO3 nanoparticles have typical orthorhombic structures that are well-crystallized.

Removal of chlorine (Cl) from the CuCl residue in the process of zinc hydrometallurgy is of great importance to improve the process economics. The current processing methods result in generation of large quantities of polluted discharge necessitating waste treatment systems. The present work attempts to de-chlorinate the CuCl residue through thermal treatment with application of microwave, towards which the effect of the major experimental factors such as roasting temperature, heating duration and particle size of samples on the process has been investigated. And the changes of Gibbs free energy (ΔG) of the dechlorination reactions are calculated which show that: 1) CuCl can react with H2O and air to produce CuO and HCl(g); 2) CuCl can be oxidized by air into CuO and Cl2 would be released. The tail gas chromatography, XRD and SEM-EDS analysis results of samples before and after microwave roasting verified the thermodynamics study results. Thus, the process of dechlorination by microwave roasting technology is feasible, and the tail gas can be mainly HCl(g) and air which can be absorbed with water and produce hydrochloride easily.

The thermal stability, crystal structures, microstructure, surface chemical functional groups and molecular structures of titania slag were characterized using TG/DSC, XRD, SEM, FT-IR and Raman spectroscopy techniques, respectively. Occurrence of two phase transformation of titania slag was identified at temperatures of 851 K and 1123 K. The weight gain of samples was observed to increase with increase in the temperature. The SEM results indicated the surface morphology of the primary particles to be tighter and smoother. Raman spectrum indicated existence of vibration band of anatase TiO