A METHOD FOR HARMLESS DISPOSAL AND RESOURCE UTILIZATION OF RESIN DESORPTION LIQUID GENERATED IN THE ION EXCHANGE PROCESS

Abstract

A method for harmless disposal and resource utilization of resin desorption liquid generated in the ion exchange process is provided. Resin desorption liquid is channeled into an electrolytic tank, which is arranged with an inlet and an outlet; the anode and the cathode within the electrolytic tank are separately connected to a stabilized power supply; both the direct and indirect oxidation process and occurred at the anode can decompose the organic pollutants in the desorption liquid; with necessary replenishment of fresh regeneration agent, the treated desorption liquid can exert excellent performance in regenerating saturated resin; the recycled use of resin desorption liquid is therefore realized, which consequently avoids unnecessary waste of regeneration agent and reduces the final yield of the desorption liquid. This method is characterized by being convenient in operation, without addition of extra reagents, without secondary pollution, and suitable for the desorption liquid with wide pH variations.

Claims

1. A method for harmless disposal and resource utilization of resin desorption liquid generated in the ion exchange process, comprising the following steps: (a) Channelling resin desorption liquid into an electrocatalytic oxidation device; said electrocatalytic oxidation device includes a stabilized power supply, an electrolytic tank, an anode and a cathode; said electrolytic tank is arranged with an inlet and an outlet; said cathode is made of graphite plate, titanium plate or titanium plate with a coating of ruthenium oxide or iridium oxide; said anode is a dimensionally stabilized titanium electrode with a coating of ruthenium oxide or iridium oxide; and (b) starting the electrocatalytic oxidation process: keeping the current density at said anode and cathode at 550 mA/cm.sup.2, the reaction time of resin desorption liquid in the electrolytic tank at 0.53 h, the distance between said anode and cathode at 1.55 cm.

2. The method for harmless disposal and resource utilization of resin desorption liquid generated in the ion exchange process as defined in claim 1, wherein the method also includes step (c): sodium chloride (NaCl) is replenished into the resin desorption liquid that has been treated by the electrocatalytic oxidation process; the mixture so obtained can be reused for regenerating saturated ion exchange resin; the replenished amount of sodium chloride accounts for 1215% (by mass) of the mixture (renewed resin regeneration agent).

3. The method for harmless disposal and resource utilization of resin desorption liquid generated in the ion exchange process as defined in claim 1, wherein in said step (a), the electrolytic tank is divided by a cation-exchange membrane from a middle into a cathode chamber and an anode chamber, and said anode and cathode are respectively located in the anode chamber and the cathode chamber respectively.

4. The method for harmless disposal and resource utilization of resin desorption liquid generated in the ion exchange process as defined in claim 1, wherein in said step (b), the current density is adjusted to 20 mA/cm.sup.2 while the reaction time is kept at 2 h.

5. The method for harmless disposal and resource utilization of resin desorption liquid generated in the ion exchange process as defined in claim 2, wherein in said step (c), NaOH is also added into the treated resin desorption liquid.

Description

EMBODIMENTS

[0022] This is further illustrated by the following embodiments.

Embodiment 1

[0023] Ion exchange resin is adopted for advanced treatment of the domestic sewage (from a Chinese city) that has undergone conventional biological treatment processes. When the resin adsorption reaches saturation, regenerate the resin with the regeneration agent (NaCl solution) for 30 min under normal temperature and pressure; the regeneration agent then turns into the desorption liquid after this regeneration process. The resin desorption liquid is then treated with an electrocatalytic oxidation device that consists of stabilized power supply, an electrolytic tank, an anode and a cathode; said electrolytic tank is arranged with an inlet and an outlet, and is divided by a cation-exchange membrane into a cathode chamber and an anode chamber; said anode and cathode are located in the anode chamber and the cathode chamber respectively; said cathode is made of graphite plate while said anode is a dimensionally stabilized titanium electrode with a coating of ruthenium oxide; channel the resin desorption liquid into the electrocatalytic oxidation device, keep the current density of the anode and cathode of the electrocatalytic oxidation device at 5 mA/cm.sup.2, the distance between the anode and the cathode at 5 cm, the reaction time within the electrolytic tank at 0.5 h; the removal rate of COD, TOC, UV.sub.254 and chromaticity reaches 42%, 26%, 55% and 95% respectively. The treated desorption liquid contains 12% (by mass) of NaCl, and can be directly reused as resin regeneration agent without replenishment of NaCl; its efficiency in regenerating saturated resin reaches 90% of that of fresh regeneration agent; after 3 times of reuse, it is subjected to final disposal as its regeneration efficiency drops down to less than 60% of that of the fresh regeneration agent. When being treated by the method disclosed herein, the amount of desorption liquid subjected to final disposal is only of that treated by other conventional methods.

Embodiment 2

[0024] Ion exchange resin is adopted for advanced treatment of the domestic sewage (from a Chinese city) that has undergone conventional biological treatment processes. When the resin adsorption reaches saturation, regenerate the resin with the regeneration agent (NaCl solution) for 30 min under normal temperature and pressure; the regeneration agent then turns into the desorption liquid after this regeneration process. The resin desorption liquid is then treated with an electrocatalytic oxidation device; the device used herein is the same with that used in embodiment 1, with exceptions as follows: said cathode is made of titanium plate while said anode is a dimensionally stabilized titanium electrode with a coating of iridium oxide; keep the current density at 20 mA/cm.sup.2, the anode-cathode distance at 4 cm, the reaction time at 2 h; the removal rate of COD, TOC, UV.sub.254 and chromaticity reaches 51%, 29%, 58% and 97% respectively. The treated desorption liquid contains 11% (by mass) of NaCl, and can be reused as resin regeneration agent after replenishment of NaCl and raising the NaCl concentration therein to 12% (by mass); its efficiency in regenerating saturated resin reaches 92% of that of fresh regeneration agent; after 4 times of reuse, it is subjected to final disposal as its regeneration efficiency drops down to less than 60% of that of the fresh regeneration agent. When being treated by the method disclosed herein, the amount of desorption liquid subjected to final disposal is only of that treated by other conventional methods.

Embodiment 3

[0025] Ion exchange resin is adopted for advanced treatment of the domestic sewage (from a Chinese city) that has undergone conventional biological treatment processes. When the resin adsorption reaches saturation, regenerate the resin with the regeneration agent for 30 min under normal temperature and pressure; the regeneration agent then turns into the desorption liquid after this regeneration process. The resin desorption liquid is then treated with an electrocatalytic oxidation device; the device used herein is the same with that used in embodiment 1, with exceptions as follows: said cathode is made of titanium plate with a coating of ruthenium oxide while said anode is a dimensionally stabilized titanium electrode with a coating of iridium oxide; keep the current density at 30 mA/cm.sup.2, the anode-cathode distance at 3 cm, the reaction time at 2 h; the removal rate of COD, TOC, UV.sub.254 and chromaticity reaches 54%, 34%, 62% and 97% respectively. The treated desorption liquid contains 11% (by mass) of NaCl, and can be reused as resin regeneration agent after replenishment of NaCl and raising the NaCl concentration therein to 12% (by mass); its efficiency in regenerating saturated resin reaches 94% of that of fresh regeneration agent; after 5 times of reuse, it is subjected to final disposal as its regeneration efficiency drops down to less than 60% of that of the fresh regeneration agent. When being treated by the method disclosed herein, the amount of desorption liquid subjected to final disposal is only of that treated by other conventional methods.

Embodiment 4

[0026] Ion exchange resin is adopted for advanced treatment of the domestic sewage (from a Chinese city) that has undergone conventional biological treatment processes. When the resin adsorption reaches saturation, regenerate the resin with the regeneration agent for 30 min under normal temperature and pressure; the regeneration agent then turns into the desorption liquid after this regeneration process. The resin desorption liquid is then treated with an electrocatalytic oxidation device; the device used herein is the same with that used in embodiment 1, with exceptions as follows: said cathode is made of titanium plate with a coating of iridium oxide while said anode is a dimensionally stabilized titanium electrode with a coating of iridium oxide; keep the current density at 40 mA/cm.sup.2, the anode-cathode distance at 2 cm, the reaction time at 2 h; the removal rate of COD, TOC, UV.sub.254 and chromaticity reaches 62%, 40%, 68% and 99% respectively. The treated desorption liquid contains 10% (by mass) of NaCl, and can be reused as resin regeneration agent after replenishment of NaCl and raising the NaCl concentration therein to 14% (by mass); its efficiency in regenerating saturated resin reaches 95% of that of fresh regeneration agent; after 6 times of reuse, it is subjected to final disposal as its regeneration efficiency drops down to less than 60% of that of the fresh regeneration agent. When being treated by the method disclosed herein, the amount of desorption liquid subjected to final disposal is only 1/7 of that treated by other conventional methods.

Embodiment 5

[0027] Ion exchange resin is adopted for advanced treatment of the domestic sewage (from a Chinese city) that has undergone conventional biological treatment processes. When the resin adsorption reaches saturation, regenerate the resin with the regeneration agent for 30 min under normal temperature and pressure; the regeneration agent then turns into the desorption liquid after this regeneration process. The resin desorption liquid is then treated with an electrocatalytic oxidation device; the device used herein is the same with that used in embodiment 1, with exceptions as follows: said cathode is made of graphite plate while said anode is a dimensionally stabilized titanium electrode with a coating of ruthenium oxide; keep the current density at 50 mA/cm.sup.2, the anode-cathode distance at 1.5 cm, the reaction time at 2 h; the removal rate of COD, TOC, UV.sub.254UV.sub.254 and chromaticity reaches 64%, 42%, 70% and 99% respectively. The treated desorption liquid contains 9% (by mass) of NaCl, and can be reused as resin regeneration agent after replenishment of NaCl and raising the NaCl concentration therein to 12% (by mass); its efficiency in regenerating saturated resin reaches 96% of that of fresh regeneration agent; after 6 times of reuse, it is subjected to final disposal as its regeneration efficiency drops down to less than 60% of that of the fresh regeneration agent. When being treated by the method disclosed herein, the amount of desorption liquid subjected to final disposal is only 1/7 of that treated by other conventional methods.

Embodiment 6

[0028] The resin desorption liquid is treated with an electrocatalytic oxidation device; the device and the operation parameters used herein are the same with those used in embodiment 5; the removal rate of COD, TOC, UV.sub.254 and chromaticity reaches 64%, 42%, 70% and 99% respectively. The treated desorption liquid contains 9% (by mass) of NaCl, and can be reused as resin regeneration agent after replenishment of NaCl and raising the NaCl concentration therein to 14% (by mass); its efficiency in regenerating saturated resin reaches 98% of that of fresh regeneration agent; after 7 times of reuse, it is subjected to final disposal as its regeneration efficiency drops down to less than 60% of that of the fresh regeneration agent. When being treated by the method disclosed herein, the amount of desorption liquid subjected to final disposal is only of that treated by other conventional methods.

Embodiment 7

[0029] The resin desorption liquid is treated with an electrocatalytic oxidation device; the device and the operation parameters used herein are the same with those used in embodiment 5; the removal rate of COD, TOC, UV.sub.254 and chromaticity reaches 64%, 42%, 70% and 99% respectively. The treated desorption liquid contains 9% (by mass) of NaCl, and can be reused as resin regeneration agent after adding new NaCl and NaOH and raising the concentration of NaCl and NaOH therein to 15% and 0.5% (by mass) respectively; its efficiency in regenerating saturated resin reaches 99% of that of fresh regeneration agent; after 7 times of reuse, it is subjected to final disposal as its regeneration efficiency drops down to less than 60% of that of the fresh regeneration agent. When being treated by the method disclosed herein, the amount of desorption liquid subjected to final disposal is only of that treated by other conventional methods.

Embodiment 8

[0030] Ion exchange resin is adopted for advanced treatment of dyeing wastewater that has undergone conventional biological treatment processes. When the resin adsorption reaches saturation, regenerate the resin with the regeneration agent for 30 min under normal temperature and pressure; the regeneration agent then turns into the desorption liquid after this regeneration process. The resin desorption liquid is then treated with an electrocatalytic oxidation device that consists of stabilized power supply, an electrolytic tank, an anode and a cathode; said electrolytic tank is arranged with an inlet and an outlet, and is divided by a cation-exchange membrane from the middle into a cathode chamber and an anode chamber; said anode and cathode are located in the anode chamber and the cathode chamber respectively; said cathode is made of graphite plate while said anode is a dimensionally stabilized titanium electrode with a coating of ruthenium oxide; channel the resin desorption liquid into the electrocatalytic oxidation device, keep the current density of the anode and cathode of the electrocatalytic oxidation device at 20 mA/cm.sup.2, the distance between the anode and the cathode at 2 cm, the reaction time within the electrolytic tank at 3 h; the removal rate of COD, TOC, UV.sub.254 and chromaticity reaches 60%, 39%, 66% and 97% respectively. The treated desorption liquid contains 9% (by mass) of NaCl, and can be reused as resin regeneration agent after replenishment of NaCl and raising the NaCl concentration therein to 12% (by mass); its efficiency in regenerating saturated resin reaches 94% of that of fresh regeneration agent; after 4 times of reuse, it is subjected to final disposal as its regeneration efficiency drops down to less than 60% of that of the fresh regeneration agent. When being treated by the method disclosed herein, the amount of desorption liquid subjected to final disposal is only of that treated by other conventional methods.

Embodiment 9

[0031] The resin desorption liquid is treated with an electrocatalytic oxidation device; the device and the operation parameters used herein are the same with those used in embodiment 8; the removal rate of COD, TOC, UV.sub.254 and chromaticity reaches 60%, 39%, 66% and 97% respectively. The treated desorption liquid contains 9% (by mass) of NaCl, and can be reused as resin regeneration agent after replenishment of NaCl and raising the NaCl concentration therein to 15% (by mass); its efficiency in regenerating saturated resin reaches 98% of that of fresh regeneration agent; after 5 times of reuse, it is subjected to final disposal as its regeneration efficiency drops down to less than 60% of that of the fresh regeneration agent. When being treated by the method disclosed herein, the amount of desorption liquid subjected to final disposal is only of that treated by other conventional methods.

Embodiment 10

[0032] The resin desorption liquid is treated with an electrocatalytic oxidation device; the device and the operation parameters used herein are the same with those used in embodiment 8; the removal rate of COD, TOC, UV.sub.254 and chromaticity reaches 60%, 39%, 66% and 97% respectively. The treated desorption liquid contains 9% (by mass) of NaCl, and can be reused as resin regeneration agent after adding new NaCl and NaOH and raising the concentration of NaCl and NaOH therein to 15% and 0.5% (by mass) respectively; its efficiency in regenerating saturated resin reaches 99% of that of fresh regeneration agent; after 5 times of reuse, it is subjected to final disposal as its regeneration efficiency drops down to less than 60% of that of the fresh regeneration agent. When being treated by the method disclosed herein, the amount of desorption liquid subjected to final disposal is only of that treated by other conventional methods.