| 摘要 |
<p>A water purification scheme employs an anionic chelating agent, such as dimethyl dithiocarbamate, as a pretreatment to bind contaminant metals and improve their removal from source water. Because conventionally employed oxidizing agents tend to dissolve downstream reverse osmosis (RO) membranes, the reducing environment created by the anionic chelating agent is inherently safer for especially sensitive thin-film composite (TFC), RO membranes. Dimethyl dithiocarbamate also acts as a mild biocide to prevent biofouling of the RO membranes. By facilitating the use of TFC membranes which have a much smaller adverse effect on the water pressure than other RO membranes, the pretreatment reducing environment enables the use of a double-pass RO membrane configuration that does not require sending product water from the first stage to a storage tank and then pumping the water from the storage tank to the second stage.</p> |
