Removal of methylene blue from aqueous solution using sediment obtained from a canal in an industrial park.

Drainage canal sediments in an industrial park are generally dredged to landfill in Taiwan. The objective of this study was to evaluate feasibility employing the sediment as an adsorbent for removal of dye. The sediment contained approximately 10% of organic matter and little heavy metals. Infrared (IR) analysis revealed that carboxyl was the most important functional group for methylene blue (MB) sorption. Canal sediment could remove the most MB from water at pH 8.0 and this removal increased with increasing temperature. The MB sorption was well described by the Langmuir, Dubinin-Radushkevich, and Temkin sorption isotherms at 10°C, but it showed good compliance with Freundlich isotherm at 25°C and 40°C. The MB adsorption was a spontaneous and endothermic reaction; its maximum calculated adsorption capacity (Qm) was 56.0 mg g-1 at 10°C by the Langmuir isotherm. The calculated values of enthalpy (ΔH°) and entropy (ΔS°) are 14.6 kJ mol-1 and 149.2 kJ mol-1, respectively. Only pseudo-second-order adsorption kinetic model successfully described the kinetics of MB onto the sediment at different operation parameters. Activation energy of MB adsorption calculated from Arrhenius equation was 16.434 kJ mol-1, indicating the binding between canal sediment and MB was a physical adsorption.

Diversity of yeasts associated with the sea surface microlayer and underlying water along the northern coast of Taiwan.

Yeast communities inhabiting the sea surface microlayer (SSML) on the northern coast of Taiwan were examined using a cultivation method and compared with those inhabiting the underlying water (UW) at a 50-cm depth. Culturable yeasts were recovered from the SSML and UW samples collected in the morning during 4 field campaigns, and 420 strains were isolated. The 420 isolates were grouped into 43 species using a polyphasic molecular approach, including sequence analysis of the 26S rDNA D1/D2 domain and 5.8S-ITS region. From the SSML samples, 12 genera and 39 species, including 7 new species of Cryptococcus sp. (1), Candida spp. (4), and Rhodotorula spp. (2), were isolated. From the UW samples, 10 genera and 21 species, including one new species of Rhodotorula sp. (1), were isolated. Rhodotorula mucilaginosa was the most abundant species present in the yeast community in SSML (37.6%) and UW (21.6%) samples. Basidiomycetous yeasts (63.6%) and pigmented yeasts (64.5%) comprised the major yeast population. The yeast community in the SSML had a higher species number and abundance than the UW. Moreover, although the majority of yeast community species were from the SSML, individual species distribution in the SSML was unequal.

Formulation factors that can reduce the formation of the phytotoxic impurity, N,N'-dibutylurea, from benomyl.

Fungicide benomyl is easily decomposed to carbendazim (MBC) and butyl isocyanate (BIC) in formulation, BIC is further hydrolyzed to butylamine. The BIC also reacts with butylamine to form N,N'-dibutylurea (DBU), a phytotoxic compound. The purpose of this study was to investigate the effects of selected additives and the manufacturing method of benomyl water dispersible granules (WG) on reducing DBU content in benomyl formulations. The manufacturing methods studied were granulation by extrusion, fluid bed spray, and spray dry. For the extrusion method, each benomyl powder formulation was homogenized by kneading with 20% v/w of 95% ethanol instead of water. After granulation, the percentages of the active ingredient benomyl and its degradation product carbendazim in each formulation were determined. For the fluid bed spray method, two formulations of wettable powders were formed. The first sample was granulated using 5% Na(2)SO(4) as the binder solution; the second sample used 2% urea. Changes in the active ingredient content after granulation were determined for each sample. For the spray dry method, four basic formulations of 70% benomyl, 5% sodium dodecyl sulfate (SDS) and 10% or 20% sodium sulfate were prepared, to study the effects of HMTA, urea and dispersant on reducing DBU formation in formulation. The DBU content of each formulation was measured for the fresh samples and after 1 year of storage. The results showed that urea had a stabilizing effect on benomyl, and reduced DBU formation. BIC increased benomyl yield during manufacturing, which reduced DBU content in fresh samples but allowed a greater potential for future DBU formation since it did not stabilize the extra benomyl. HMTA was found to reduce DBU in both aqueous BIC and prepared formulations. The study discusses how each of the selected constituents affected DBU formation and how commercial formulations can be improved to reduce DBU formation. From this study, it is clear that a safer benomyl formulation can be developed.