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As salicylic acid (SAC) is an extensively used pharmaceutical, discharge of SAC into the environment has caused serious threats to ecology in view of its toxicity. Therefore, SO4•−-involved chemical oxidation methods have been employed for eliminating SAC. Since monopersulfate (MPS) has become a popular reagent for producing SO4•−, an alternative heterogeneous Co-based catalyst is proposed by using a Co-coordinated covalent organic polymers (Co-COP) as a precursor. Via carbonization, Co-COP is transferred by conversion of Co ions to Co/CoO nanoparticle and conversion of COP to N-doped carbon nanocapsules (CNC), respectively, to form a unique composite of Co NPs embedded into carbon nanocapsule (CoCNC). CoCNC exhibits a higher catalytic activity than Co3O4 nanoparticle for activating MPS to degrade SAC because of synergistic effects between Co NPs and the N-doped CNC which not only acts as the support but also provides active sites. Hence, CoCNC+MPS could afford a much lower Ea value (25.4 kJ/mol) of SAC degradation than the reported values. Moreover, CoCNC is still efficient for removing SAC even in the presence of high-concentration NaCl and SDS. CoCNC can be also recyclable over many cycles and maintain its catalytic activities, confirming that CoCNC is an advantageous catalyst for MPS activation.

This study investigated the influence of holiday characteristics and numbers of vacation days on the “holiday effect” of three crucial Chinese holidays in Taipei. Surface measurements of NOx, CO, NMHC, O3, SO2, and PM10 from 13 air quality-monitoring stations of the Taiwan Environmental Protection Administration (TEPA) in the Taipei metropolitan area during holiday and non-holiday periods of 1994–2012 were used. All six pollutants were proven to exhibit holiday effects between Chinese New Year (CNY) and non-Chinese New Year (NCNY) periods. However, almost all pollutants exhibited holiday effects for the two other holidays; the exceptions were O3 between Tomb Sweeping Day (TSD) and non-Tomb Sweeping Day (NTSD) periods and CO and PM10 between Mid-Autumn Day (MAD) and non-Mid-Autumn Day (NMAD) periods. Air pollutants, including NOx, CO, NMHC, SO2, and PM10, that exhibited holiday effects had consistently lower concentrations in holiday periods than in non-holiday periods, whereas O3 concentrations were higher in holiday periods than in non-holiday periods. A widespread holiday effect with consistent signs indicates a high degree of urbanization in the study area. Compared with CNY–NCNY and MAD–NMAD periods, the TSD–NTSD period had a considerably lower difference of the titration effect, lower NOx resulting in less ozone destruction, in evening traffic hours and an inconsistent holiday effect in the daytime and nighttime, leading to the lack of O3 holiday effect. Because the MAD period had more nighttime activities than the other two holiday periods did, the MAD–NMAD period lacked CO and PM10 holiday effects. The prevalently higher ratios of CO, NMHC, SO2, and PM10 relative to NOx as a proxy of mobile sources and a lower PM2.5/PM10 ratio in the MAD period than in the CNY and TSD periods indicate different pollution sources oriented from holiday activities. The air pollutants exhibited a weakening trend are all associated with a greater improvement in air quality during the non-holiday periods than the holiday periods, which implies successful air pollution control policies. Holiday effects of NOx, NMHC (p

Introduction – Because of its chemical diversity, the only way to standardise propolis is to specify multiple standards for diff erent propolis types according to the corresponding chemical profi le. So far, this has been done only for European propolis. Objective – To develop a rapid low-cost spectrophotometric procedure for quantifi cation of bioactive prenylated fl avanones in Taiwanese propolis. Methodology – The proposed method quantifi es the total fl avanones on the basis of their absorption as coloured phenylhydrazones formed by interaction with 2,4-dinitrophenylhydrazine. The procedure was validated through model mixture of compounds representing the composition of Taiwanese propolis according to previous studies. The major fl avanones of the propolis samples (propolins C, D, F and G) were quantifi ed by HPLC. Antiradical activity against DPPH was also measured. The DNP (dinitrophenylhydrazine) spectrophotometric method is applied for the fi rst time for quantifi cation of prenylated fl avanones. Results – Spectophotometric procedure applicable to new type propolis (Macaranga type) was developed with recovery between 105 and 110% at the concentration range of 0.573–1.791 mg/mL. Six propolis samples were analysed by spectrophotometry using the procedure developed and validated, and by HPLC as the results demonstrated satisfactory agreement. Neither the spectrophotometric data nor the values measured by HPLC showed signifi cant correlation with the antiradical activity against DPPH. Conclusion – The proposed spectrophotometric procedure is useful for routine analyses of Macaranga-type propolis, because of its simplicity, repeatability and acceptable accuracy. Its application to a number of commercial samples could be used as a basis for standardisation and quality control of Pacifi c propolis. Copyright © 2009 John Wiley & Sons, Ltd.

The efficiency of arsenic removal from source waters and artificial freshwaters during coagulation with ferric chloride and alum was examined in bench-scale studies. Arsenic(V) removal by either ferric chloride or alum was relatively insensitive to variations in source water composition below pH 8. At pH 8 and 9, the efficiency of arsenic(V) removal by ferric chloride was decreased in the presence of natural organic matter. The pH range for arsenic(V) removal with alum was more restricted than with ferric chloride. For source waters spiked with 20 μg/L arsenic(V), final dissolved arsenic(V) concentrations in the product water of less than 2 μg/L were achieved with both coagulants at neutral pH. Removal of arsenic(III) from source waters by ferric chloride was both less efficient and more strongly influenced by source water composition than removal of arsenic(V). The presence of sulfate (at pH 4 and 5) and natural organic matter (at pH 4 through 9) adversely affected the efficiency of arsenic(III) removal by ferric chloride. Arsenic(III) could not be removed from source waters by coagulation with alum.

Bench-scale studies were conducted in model freshwater systems to investigate how various parameters affected arsenic removal during coagulation with ferric chloride and arsenic adsorption onto preformed hydrous ferric oxide. Parameters included arsenic oxidation state and initial concentration, coagulant dosage or adsorbent concentration, pH, and the presence of co-occurring inorganic solutes. Comparison of coagulation and adsorption experiments and of experimental results with predictions based on surface complexation modeling demonstrated that adsorption is an important (though not the sole) mechanism governing arsenic removal during coagulation. Under comparable conditions, better removal was observed with arsenic(V) [As(V)] than with arsenic(III) [As(III)] in both coagulation and adsorption experiments. Below neutral pH values, As(III) removal-adsorption was significantly decreased in the presence of sulfate, whereas only a slight decrease in As(V) removal-adsorption was observed. At high pH, removal-adsorption of As(V) was increased in the presence of calcium. Removal of As(V) during coagulation with ferric chloride is both more efficient and less sensitive than that of As(III) to variations in source water composition.