The influence of black carbon on the sorption and desorption of two model PAHs in natural soils.

Black carbons (BC) which result from the incomplete combustion of farm waste [man-made (burned) BC] are highly absorbent. In Taiwan, the burning of farm waste known as slash and burn is common. The BCs from the burning may present an environmental challenge.

Quick determination of malodor-causing fatty acids in manure by capillary electrophoresis.

The analysis of odor components in livestock waste has been extensively studied. Past research has identified volatile fatty acids, especially from C3 to C6, as indicators of malodor. Originally, the odorous components were analyzed by gas chromatography after a tedious absorption and troublesome extraction procedure or by a subjectively olfactory system or sense of smell.

Evaluating the efficiency of coagulation in the removal of dissolved organic carbon from reservoir water using fluorescence and ultraviolet photometry.

The present study used ultraviolet absorption (UVa) and the florescence intensity (FI) to evaluate the coagulation efficiency for removing dissolved organic carbon (DOC) in the raw water from Min-Ter, Li-Yu-Ten and Yun-Ho-Shen reservoirs in Taiwan. The results indicated that the ratio of DOC removal rate and FI removal rate was maintained at about 1 at various coagulant dosages. However, the ratio of DOC removal rate and UVa removal rate decreased as the coagulant dosage increased.

Kinetic study on the sorption of dissolved natural organic matter onto different aquifer materials: the effects of hydrophobicity and functional groups.

The subsurface sorption of Suwannee River fulvic acid (SRFA) and humic acid (SRHA) onto a synthetic aquifer material (iron-oxide-coated quartz) and two natural aquifer materials (Ringold sediment and Bemidji soils) was studied in both batch and column experiments. The hypothesis that hydrophobic effects followed by ligand exchange are the dominant mechanism contributing to the chemical sorption happening between dissolved natural organic matter (NOM) and the mineral surfaces is supported by observations of several phenomena: nonlinear isotherms, faster sorption rates versus slower desorption rates, phosphate competition, a solution pH increase during NOM sorption, and functional groups and aromaticity-related sorption. In addition, high-pressure size exclusion chromatography (HPSEC) and carboxylic acidity showed that lower molecular weight NOM components of SRHA are preferentially sorbed to iron oxide, a result in contrast to that for SRFA.

Transport of anthracene and benz(a)anthracene through iron-quartz and three aquifer materials in laboratory columns.

In groundwater systems, dissolved natural organic matter (NOM) can influence the mobility of organic contaminants by altering the contaminant behavior in water and solid phases. The transport of anthracene and benz(a)anthracene (B(a)A) was studied in the presence and absence of NOM and/or soil organic matter (SOM) in column experiments. The results show that sorption are related to the properties of polycyclic aromatic hydrocarbons (PAHs), NOM and SOM.

Effect of phosphate on removal of humic substances by aluminum sulfate coagulant.

The presence of humic acid may change the way phosphate is absorbed or stabilized by soil and how it influences the growth of plants. The binding of phosphate with the humic substance requires bridging between phosphate ions and humic acid by metal ions, such as aluminum or iron ions. The bridging reaction can take place in peat and allophane soil under acidic conditions, altering the effectiveness of the phosphate in soil.

Influence of eutrophication on the coagulation efficiency in reservoir water.

Water from the three reservoirs, Min-ter, Li-yu-ten and Yun-ho-shen, was examined for concentration of chlorophyll a, ultraviolet absorption (UV(254)), fluorescence intensity (FI), concentration of dissolved organic carbon (DOC), and fractionation of dissolved molecules by molecular weight. The water samples were collected over the change from spring to summer (May to July but before the typhoon season) when the water temperature and extent of eutrophication increase. Analytical results indicate that the concentration of DOC is proportional to the concentration of chlorophyll a, but not to the values of UV(254) and FI.

A study of coagulation mechanisms of polyferric sulfate reacting with humic acid using a fluorescence-quenching method.

A fluorescence-quenching method is developed to assess the effect of pH on the coagulation mechanism of humic acids (HA) reacting with metal ions. A polyferric sulfate (PFS) synthesized in our laboratory is adopted as the coagulant to simplify the hydrolysis process and increase the experimental precision. The following results are discovered.