A process for removing contaminants from large volumes of wastewater is disclosed. The process involves treating a wastewater stream containing the contaminant with a coagulant that reacts with the contaminant to form a particulate or aggregate of particulates having a size greater than 10 μm. The treated wastewater is passed through a microfiltration membrane having a pore size in the range from 0.5 μm to 10 μm at low pressure (less than 20 psig) to remove the contaminant. Under such conditions, the treated wastewater flux rate is greater than 200 gallons per square foot of membrane per day (“GFD”), and typically from 200 to 1500 GFD.

Process and apparatus for high flow and low pressure impurity removal

Although large quantities of dithiocarbamate fungicides and ethylxanthogenate mineral flotation agents are released routinely to the environment, little is known about their fate and effects because sensitive analytical techniques are not available. A simple and selective HPLC method for trace level analysis of dithiocarbamate fungicides and xanthogenates (dithiocarbonates) in natural waters has been developed. The method is based on the in situ formation of a 1:1 Cu(II)−dithioligand complex and its separation as an ion pair with hexanesulfonate on a C-18 reversed-phase column. The compounds are detected at the wavelength of maximum absorption of the Cu(II)−ligand complex (260−287 nm). Method detection limits are 20 nM dimethyldithiocarbamate (i.e., 3 μg/L Ziram), 33 nM ethylenebis(dithiocarbamate) (i.e., 9 μg/L Maneb), and 23 nM ethylxanthogenate (i.e., 4 μg/L). An on-line preconcentration step can be used to lower the detection limits by a factor of 5−10.

Analysis of the Dithiocarbamate Fungicides Ziram, Maneb, and Zineb and the Flotation Agent Ethylxanthogenate by Ion-Pair Reversed-Phase HPLC

Preconcentration of certain anions using reagents immobilized via silylation

Decomposition of monoalkyl dithiocarbamates

Second harmonic a.c. polarography. Theoretical predictions for systems with first-order chemical reactions following the charge transfer step

Studies on the stability of dithiocarbamic acids.

Studies on sensitivity in atomic absorption spectroscopy of nickel, tin, titanium, zirconium, hafnium, niobium, and tantalum, as metallocenes and as simple salts or oxy-salts, have shown that the m...

Effect of metal–oxygen bond on the sensitivity of atomic-absorption spectroscopic technique

Studies on the solvent extraction of morpholine dithiocarbamic acid complexes of divalent metal ions Mn, Fe, Co, Ni, Cu, Zn, Pb, Cd, Hg, and Sn were carried out, and the extraction constants and the overall stability constants were determined. The stability constants of complexes of Cu(II) formed with various substituted dithiocarbamic acids, showed a variation of the stability constants with the basicity of the nitrogen and sulfur atoms in the reagents.

Vedula S. Sastri

Papers

Studies on the stability of dithiocarbamic acids.

Effect of metal–oxygen bond on the sensitivity of atomic-absorption spectroscopic technique

Studies on the solvent extraction of metal dithiocarbamates