Method for electrolysis-ozone-corrosion inhibitor/electrolysis-ozone-hydrogen peroxide-corrosion inhibitor coupling treatment on toxic and refractory wastewater

Patent metadata

Field	Value
Publication number	US-11548797-B2
Application number	US-202017763229-A
Country	US
Kind code	B2
Filing date	Oct 13, 2020
Priority date	Oct 14, 2019
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

A method for electrolysis-ozone-corrosion inhibitor/electrolysis-ozone-hydrogen peroxide-corrosion inhibitor coupling treatment on toxic and refractory wastewater includes the following steps: adding toxic and refractory wastewater to be treated into a wastewater treatment reaction tank equipped with a plate anode and a plate cathode, and starting a direct current (DC) power supply connected to the plate anode and the plate cathode to treat the toxic and refractory wastewater at an appropriate current density under stirring, during which a corrosion inhibitor and hydrogen peroxide are added to the toxic and refractory wastewater to be treated and ozone is introduced into the toxic and refractory wastewater to be treated through an aeration device. The method can increase the production rate and production quantity of free radicals in a reaction system, effectively improve the treatment efficiency for toxic and refractory wastewater, and reduce the treatment cost.

First claim

What is claimed is:

1. A method for electrolysis-ozone-corrosion inhibitor/electrolysis-ozone-hydrogen peroxide-corrosion inhibitor coupling treatment on toxic and refractory wastewater, wherein
a wastewater treatment reaction tank used in the method is composed of a cylindrical tank body with a closed lower end and an open upper end, and a sealing cover arranged at the open end of the tank body;
a stirring device is provided inside the cylindrical tank body; a water inlet pipe, a water outlet pipe, an ozone delivery pipe, a corrosion inhibitor feeding pipe, and a hydrogen peroxide feeding pipe are provided on the cylindrical tank body; the sealing cover arranged at the open end of the cylindrical tank body is a conical cover body, and a residual ozone discharge pipe is provided at a top end of the conical cover body;
the residual ozone discharge pipe is connected to a residual ozone removal device provided to remove unused ozone during a toxic and refractory wastewater treatment process; a first end of the ozone delivery pine is connected to an ozone generator outside the cylindrical tank body, and a second end is located inside the cylindrical tank body and connected to an aeration device;
the corrosion inhibitor feeding pipe communicates with a corrosion inhibitor solution storage tank through a peristaltic pump, the hydrogen peroxide feeding pipe communicates with a hydrogen peroxide solution storage tank through a peristaltic pump, and the water inlet pine communicates with a to-be-treated toxic and refractory wastewater reservoir through a water inlet pump; the stirring device is a mechanical stirring device or a magnetic stirring device;
a plate anode and a plate cathode are arranged in the wastewater treatment reaction tank; shapes and areas of the plate anode and the plate cathode are identical, and the plate anode and the plate cathode are rectangular; the plate anode and the plate cathode are parallel to each other and are parallel to an axis of the cylindrical tank body; the plate anode and the plate cathode are arranged at the same height; the areas of the plate anode or the plate cathode are 40% to 80% of an area of a longitudinal section of the wastewater treatment reaction tank; and a distance between the plate anode and the plate cathode is 20% to 60% of a diameter of the wastewater treatment reaction tank; the plate anode and the plate cathode are connected to a direct current (DC) power supply through an electric wire; the plate anode and the plate cathode are selected from the group consisting of iron plates, stainless steel plates, aluminum plates, and aluminum oxide plates;
the method comprises:
preparing a corrosion inhibitor into a corrosion inhibitor solution and storing the corrosion inhibitor solution in the corrosion inhibitor solution storage tank;
preparing hydrogen peroxide into a hydrogen peroxide solution and storing the hydrogen peroxide solution in the hydrogen peroxide solution storage tank;
pumping toxic and refractory wastewater to be treated by the water inlet pump into the wastewater treatment reaction tank through the water inlet pipe until the toxic and refractory wastewater to be treated at least submerges the plate anode and the plate cathode;
starting the DC power supply connected to the plate anode and the plate cathode to treat the toxic and refractory wastewater at a current density of 1 mA/cm 2 to 100 mA/cm 2 under stirring, wherein the time of treating the toxic and refractory wastewater is controlled to be not more than 60 min;
during the toxic and refractory wastewater treatment process, pumping the corrosion inhibitor into the wastewater treatment reaction tank by the peristaltic pump through the corrosion inhibitor feeding pipe, pumping the hydrogen peroxide solution into the wastewater treatment reaction tank by the peristaltic pump through the hydrogen peroxide feeding pipe, and introducing ozone generated by the ozone generator into the toxic and refractory wastewater to be treated through the ozone delivery pipe and the aeration device;
introducing unreacted ozone in the wastewater treatment reaction tank into the residual ozone removal device through the residual ozone discharge pipe for removal; and
discharging the wastewater through the water outlet pipe after the toxic and refractory wastewater treatment process is completed;
wherein the corrosion inhibitor is at least one from the group consisting of silicate, chromate, molybdate, phosphate, polyphosphate, and polysilicate, a rate of the hydrogen peroxide is controlled to be at 0 mmol/h or 1 mmol/h to 100 mmol/h per liter of an effective volume of the wastewater treatment reaction tank.

2. The method according to claim 1 , wherein the corrosion inhibitor is added in the form of the corrosion inhibitor solution to the wastewater treatment reaction tank during the toxic and refractory wastewater treatment process, and the corrosion inhibitor is added at an amount of 1 mmol/h to 100 mmol/h per liter of the effective volume of the wastewater treatment reaction tank.

3. The method according to claim 1 , wherein the ozone is introduced into the toxic and refractory wastewater to be treated through the aeration device at an amount of 1 g/h to 50 g/h per liter of the effective volume of the wastewater treatment reaction tank.

4. The method according to claim 1 , wherein the aeration device is an aeration plate, an aerator, or a microporous gas diffuser.

5. The method according to claim 1 , wherein a pH of the toxic and refractory wastewater to be treated is 3 to 10.5.

Assignees

• Univ Sichuan

Inventors

• Lai Bo
• Xiong Zhaokun
• Pan Zhicheng
• Liu Yang
• Zhou Peng
• Zhang Heng
• He Chuanshu
• Li You

Classifications

• C02F1/461 Primary

  by electrolysis · CPC title

• Y02W10/37

  using solar energy · CPC title

• C02F1/78

  with ozone {(C02F1/4672 takes precedence)} · CPC title

• C02F2201/784

  Diffusers or nozzles for ozonation · CPC title

• C02F2001/46152

  characterised by the shape or form · CPC title