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The presence of nondegradable organic compounds and xenobiotic chemicals in water is a great concern for the general public because of their polar properties and toxicity. For instance, trichloroethylene (TCE) is a widely used solvent in the chemical industry, and it is also a contaminant of soil, surface water, and groundwater. Recent studies on new treatment technologies have shown that photocatalyst-based advanced oxidation processes are appropriate for removing these polar and toxic compounds from water. The objective of this study was to remove TCE from water using novel nano-ZnO-laponite porous balls prepared from photocatalyst ZnO with nanoscale laponite. These nano-ZnO-laponite porous balls have a porosity of approximately 20%. A lower initial concentration of TCE resulted in high removal efficiency. Moreover, the removal efficiency increased with increasing pH in the photocatalytic degradation experiments employing UVC light with nano-ZnO-laponite. The optimal dosage of nano-ZnO-laponite was 30 g and the use of UVC light resulted in a higher removal efficiency than that achieved with UVA light. In addition, the removal efficiency of TCE significantly increased with increasing light intensity. We think that TCE’s removal in water by using porous ball of nano-ZnO and nanoclay composite is a result of degradation from hydroxide by photons of nano-ZnO and physical absorption in nanoclay.

In this study, we investigated a mechanism of carbonation reaction by CO2 capture through synthesis of ternary (CaO-Al2O3-Fe2O3) compounds. As for the composition of the sintered calcium aluminum ferrite (SCAF), the proportions of CF-based product and CA-based product were high, at 87.3% and 64.6%, at sintering temperatures of 1000 °C and 1100 °C, respectively. In addition, in the process of both dry and wet carbonation, the carbonation reaction occurred in the synthetic SCAF regardless of the sintering temperature conditions. In particular, in the carbonation with the wet method, CAH and CAFH, which are hydrates, were produced in up to 1 h of the reaction time with CO2, but from 3 h of reaction time, carbo compounds such as calcium carbo aluminate and calcium carbo alumino-ferrite compounds were produced. That is, with increasing reaction time, the carbo reaction becomes more active in the process. Therefore, SCAF synthesized in this study easily produced carbo compounds through carbonation reactions and formed carbonates by reaction with CO2. Thus, it is expected that the compounds can be effectively utilized as an excellent material for CO2 capture capable of CO2 absorption and fixation.

This paper describes the CO2 capture performance of cement blended paste incorporating gamma-dicalcium silicate (gamma-C2S) made with industrial by-products, by taking into consideration of eect of CaCO3, y ash replacement ratio under the sintering process. X-ray diraction method was conducted in order to quantitatively investigate the gamma-C2S content. CO2 capture performance of mortar sample incorporating gamma-C2S was investigated by means of compressive strength test using accelerated carbonation chamber. The experimental results revealed that the kind of CaCO3 would aect the aect the formation of gamma-C2S after the sintering with respect to the XRD-Rietveld analysis. Moreover, it is conrmed that compressive strength of mortar sample incorporating gamma-C2S has the same tendency at curing age of 3, 7 and 28days. Blended mortar sample made with 10 wt.% replacement ratio of gamma-C2S had high compressive strength value compared to normal mortar sample, therefore, incorporating gamma-C2S had a positive eect on the compressive strength after accelerated carbonation. Finally, the waste foundry sand powder may be alternative to produce gamma-C2S.