Patent No. 11,754,778

Description:


Abstract:
In recent years, the photoresponsive polymers and othersmart materials have been considered indrug deliveryor other applications.Photons of light canactuate the structure of photoresponsive polymer structures (cages). This concept is used in trapping/releasing chemicalsfrom water and onto the polymer by closing/opening folded polymer structure. Various types of stimuli could be used in activating these polymers that include light, pH, temperature, electric, magnetic fields and/or ultrasounds (Wu, 2017). Among them, light as an external stimulus is found to be advantageous, especially in the drug delivery application for a number of reasons. Light is noninvasive, convenient;with ease of use provides better temporal control. Light mediated photoresponsive polymers canbe to incorporate with the recent advancement of an efficient light delivery system using coated optical fibers in reducing contaminant of interest from water (Westerhoff, 2017). Visible or UV light launched from thefiber opticcore undergoes refraction on the fiber edge, which is coated with photoresponsive polymers. When the light is on, the polymer adsorbs inorganic or organic ions from a flowing stream of water. When the water flow is turned-offand the light is cycled off, the polymer changes toitsoriginal configuration and releases theseions, which can then be flushed away into a wastestream. Cycling flow and light allowsemi-continuous treatment of water. This process replaces ion exchange polymer, whichrequireshigh strength salts or pH variations to adsorbed/desorb ions from the polymer, using light instead.Unlike these chemical ion exchange processes that generate concentrated brine or extreme pH solutions containing low concentrations of the pollutant from the water –the photoresponsive polymer releases only the pollutant into water (i.e., no concentrated salt, acid or alkaline brines are generated).Light actuates photoresponsive polymer structure or functional groups, i.e., it transforms the polymer in opening or closing its structure or transformingthem indevelopingcharges in acting as an ion-exchanger to complex with targeted cations (such as metals Ca, Mg, Cu, Li, etc.) or anion (such as arsenic, phosphate, etc.) in flowing water. Thus, capturethese contaminants selectively onto these polymer surfaces by such activationprocess. Once adsorbed thelight is then turned off, which changes these polymers to its original shape or as a non-charge (non-ionic) structure to dislodge the adsorbed contaminant (cations/anions) back into solution or as waste which is flushed out of the system. This operation can continue seamlessly in water treatment, with simple turning on/off with the lightsource(visible, IR, UV wavelengths from LED, white light, black lamp, etc. sources). Such a system is expected to be simple, with no chemical additionand can operate continuouslywithout much of disruptions.This technology can be used in softening water, i.e., removing divalent cations such as calcium and magnesium from water. An elevated amount of these cations in water can cause severe scaling issues to various water treatment units (e.g., pipes, heat exchanger, boiler, membranes, etc.) and other water treatment processes. The technology will not be limited to drinking water but can serve industrial water or produced water from an oil-gas operation. It can also be applied to recovering precious metals, such as lithium, cadmium, copper, zinc, etc. from water or in removing valued anions, such as phosphates or other renewable resources from enriched waste streamsor toxic anions such as arsenate from water.


UTEP Docket No: 2019-002