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This study investigated the degradation of anthraquinone reactive dye C.I. Reactive Blue 19 (RB-19) with initial concentration of 100mg L(-1) in aqueous solution by ozone oxidation. The results of UV/VIS and FTIR spectra showed that the anthraquinone structures, nitrogen linkages and amino groups of RB-19 were destroyed under direct ozone reaction. The identification by LC-MS and GC-MS analyses indicated that some organic acids (e.g., phthalic acids) and 1,3-indanone could be the primary degradation products, respectively. The Microtox toxicity of the ozonated RB-19 solution initially increased but subsequently decreased when ozonation time increased. This detoxification accompanied biodegradability enhancement revealed by BOD/COD ratio increasing from 0.15 to 0.33 after 10min of ozonation.

This study found that MCB photolysis, attacked by ·OH radicals, yielded 2-chlorophenol (2CP), 4-chlorophenol (4CP), 3-chlorocatechol (3-CC), chlorohydroquinone (CHQ), and 4-chlorocatechol (4-CC) as the aromatic intermediates. Oxalic acid was also found as ring opened intermediate. Experimental results showed that hydroxylation occurred prior to the dechlorination preceding ring cleavage. The illumination times for complete dechlorination and ring cleavage of the MCB were 20 minutes and 40 minutes, respectively. After ring cleavage, other reactions were needed to mineralize the organic acids into carbon dioxide and water.

In this study, marble sludge, sewage sludge, drinking water treatment plant sludge, and basic oxygen furnace sludge were used as replacements for limestone, sand, clay, and iron slag, respectively, as the raw materials for the production of cement in order to produce eco-cement. It was found that it is feasible to use marble sludge to replace up to 50% of the limestone and also that other materials can serve as total replacements for the raw materials typically used in the production of cement. The major components of Portland cement were all found in eco-cement clinkers. The eco-cement was confirmed to produce calcium hydroxide and calcium silicate hydrates during the hydration process, increasing densification with the curing age. The compressive strength (S(c)) and microstructural evaluations conducted at 28 d revealed the usefulness of eco-cement. It was observed that the S(c) data correlated linearly with the pore volume (P) data at 28 d. The proposed model equation could be represented as S(c)=178-461P (correlation coefficient, R(2)=0.96). Two parameters, the large capillary pore volume and the medium capillary pore volume, were evaluated using multiple regression analysis.

The reaction sequence for the photocatalytic degradation of monochlorobenzene (MCB) in UV/TiO 2 process, including substrate adsorption, degradation, and mineralization, was studied. The theoretical maximum quantity of MCB that could be adsorbed onto TiO 2 surface in aqueous phase was 0.18 ± 0.04 μmol m −2 of TiO 2 . In accordance with the upper limit of the relative surface coverage of MCB molecules to surface hydroxyls of TiO 2 was around 2.2%, the water molecules as the major adjacent species near TiO 2 surface would compete with MCB molecules. Increasing the initial substrate concentration to an appropriate value or enhancing the affinity between the MCB and the TiO 2 surface by adjusting the solution pH would promote the photocatalytic degradation. Experimental results revealed that the neutral medium was beneficial for the degradation of MCB. In comparison, the mineralization was most improved at acidic condition. Generally, 90% of the total organic carbon (TOC) was mineralized after 240 min illumination time in the examined pH range except solution pH 11. The suppressed mineralization of MCB at solution pH 11 was ascribed to the lack of adsorption. A simplified 2-step consecutive kinetic model was used to simulate the mineralization.