Double-layer nested fixed bed device for removing methylene blue

Abstract

A double-layer nested fixed bed device for removing methylene blue belongs to the field of wastewater treatment and comprises a fixed bed adsorption column, a peristaltic pump, a water inlet tank, a water storage tank and a guide pipe, one end of the peristaltic pump is connected with a first water inlet at the lower end of the fixed bed adsorption column through the guide pipe, and the other end of the peristaltic pump is communicated with a second water outlet of the water inlet tank through the guide pipe. A first water outlet of the fixed bed adsorption column is communicated with a third water inlet of the water storage tank through a guide pipe, the upper and lower ends in the fixed bed adsorption column are filled with quartz sand, and the middle in the fixed bed adsorption column is filled with a porous composite material; the solid-liquid separation device systematically solves the solid-liquid separation problem of the traditional powder adsorption process through an adsorbent immobilization strategy and a fluid dynamics optimization scheme.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment, and specifically relates to a double-layer nested fixed bed device for removing methylene blue. Background Technology

[0002] The textile dyeing and printing industry ranks fifth in wastewater discharge among all industrial sectors in China, accounting for 7.5% of the national industrial wastewater discharge, with an annual discharge of approximately 1.13 billion tons (accounting for 80% of the textile dyeing and printing industry's wastewater), and a daily discharge of 3-4 million tons. Dyeing and printing wastewater contains dyes, auxiliaries, heavy metals (such as chromium and lead), formaldehyde, and other toxic and harmful substances. It is characterized by high color intensity, high chemical oxygen demand, and high salinity; every ton of dyeing and printing wastewater discharged can pollute 20 tons of water bodies. Methylene blue, as a typical cationic azo dye, has extremely stable chemical properties and is difficult to remove through oxidation or photocatalytic degradation. Furthermore, methylene blue has teratogenic and biotoxic properties; long-term presence in the environment may have toxic effects on aquatic organisms and affect aquatic ecosystems. Human exposure to methylene blue can also cause various serious consequences, including Henlein body anemia, altered red blood cell morphology, and necrotizing abscesses. Adsorption is a typical technology for treating methylene blue dye in dyeing and printing wastewater, and its effectiveness has been verified through the development of various adsorbents. Studies have shown that porous adsorption systems, including activated carbon, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs), can achieve methylene blue removal rates of over 90% based on strategies for specific surface area regulation and adsorption site optimization. However, powdered adsorbents are prone to problems such as solid-liquid separation difficulties, material loss, and blockage of continuous flow systems during dynamic treatment. Developing composite materials can significantly improve their engineering applicability, dynamic adsorption capacity, and cycle stability, thus adapting them to the engineering requirements of fixed-bed devices. In addition, the continuous flow design of fixed beds can maintain stable hydraulic conditions, and combined with the regeneration capability of composite materials, it significantly reduces the cost of large-scale applications. Traditional single-layer fixed-bed adsorption columns suffer from problems such as high pressure drop in the packing layer and uneven mass transfer efficiency, leading to a decrease in treatment efficiency over time. Therefore, a multi-layer nested structure was developed to achieve deep removal of pollutants through staged adsorption, ultimately constructing a dyeing and printing wastewater treatment system that combines high efficiency and economy. Summary of the Invention

[0003] To address the aforementioned issues, this invention proposes a double-layer nested fixed bed device for removing methylene blue, achieving a synergistic improvement in both structural compactness and adsorption kinetics performance. This device is simple in structure and easy to operate.

[0004] A double-layer nested fixed-bed device for removing methylene blue includes a fixed-bed adsorption column, a peristaltic pump, an inlet tank, a storage tank, and conduits. The fixed-bed adsorption column includes a base, a top cover, an inner tube, and an outer tube. The outer tube is sleeved over the inner tube, and the height of the inner tube is lower than that of the outer tube. Both the inner and outer tubes are mounted on the base. The top cover is fixed to the upper surface of the outer tube. A sealing gasket is placed between the top surface of the outer tube and the top cover for sealing. A first water inlet is provided at the bottom of the inner tube; a first water outlet is provided on the side wall of the outer tube. The lower part of the inlet tank has... The second water outlet is located at the top of the water inlet tank, the third water inlet is located at the top of the water storage tank, and the third water outlet is located at the bottom of the water storage tank. One end of the peristaltic pump is connected to the first water inlet at the bottom of the fixed bed adsorption column through a conduit, and the other end of the peristaltic pump is connected to the second water outlet of the water inlet tank through a conduit. The first water outlet of the fixed bed adsorption column is connected to the third water inlet of the water storage tank through a conduit. The upper and lower ends of the fixed bed adsorption column are filled with quartz sand, and the middle of the fixed bed adsorption column is filled with porous composite material.

[0005] The porous composite material is a Zr-MOG / SA beads composite microsphere.

[0006] The preparation method of the Zr-MOG / SA beads is as follows:

[0007] 0.1726 g of ZrOCl2⋅8H2O and 0.1576 g of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine were dissolved in 1 mL of ethanol and 5 mL of dimethyl sulfoxide, respectively. The two solutions were sonicated until completely dissolved and then mixed. The mixture was transferred to a drying oven and heated at 120 °C for 12 h. The resulting wet gel was dialyzed and then freeze-dried to obtain Zr-MOG powder.

[0008] Weigh out equal amounts of Zr-MOG powder and sodium alginate, dissolve them separately in water, mix the two solutions thoroughly, and then add them dropwise to a 1 wt% CaCl2 solution. Let stand for 12 h, and wash with deionized water 3 to 4 times to obtain Zr-MOG / SAbeads.

[0009] Zr-MOG is a zirconium-based organometallic gel, and Zr-MOG / SA beads are zirconium-based organometallic gel / sodium alginate composite microspheres.

[0010] The working process and working principle of this utility model:

[0011] The methylene blue wastewater in the storage tank enters the inner tube of the fixed bed adsorption column at a constant flow rate through the first inlet of the fixed bed adsorption column by the action of a peristaltic pump. After passing through the adsorption zone composed of quartz sand and porous composite material, the methylene blue is deposited on the surface of the adsorbent. The filtrate overflows from the inner tube of the fixed bed adsorption column to the outer tube, and finally flows into the storage tank from the first outlet of the fixed bed adsorption column. While maintaining continuous treatment of dyeing and printing wastewater, it also ensures the efficient removal of methylene blue.

[0012] The beneficial effects of this utility model are:

[0013] Traditional dyeing and printing wastewater treatment typically involves directly adding adsorbents, which then need to be recovered through filtration. However, this invention systematically solves the solid-liquid separation problem of traditional powder adsorption processes by employing an adsorbent immobilization strategy and a fluid dynamics optimization scheme. The adsorbent immobilization strategy refers to a porous composite material loading system, and the fluid dynamics optimization scheme refers to a bottom-in, bottom-out bidirectional flow design. Attached Figure Description

[0014] Figure 1 This is a structural force diagram of an embodiment of the present utility model;

[0015] Figure 2 This is a cross-sectional view of the fixed-bed adsorption column according to an embodiment of the present invention. Detailed Implementation

[0016] Please see Figure 1 and Figure 2 As shown, a double-layer nested fixed-bed device for removing methylene blue includes a fixed-bed adsorption column 1, a peristaltic pump 2, an inlet tank 3, a storage tank 4, and a conduit 5. The fixed-bed adsorption column includes a base 11, a top cover 15, an inner tube 16, and an outer tube 17. The outer tube 17 is fitted over the inner tube 16, and the height of the inner tube 16 is lower than that of the outer tube 17. Both the inner tube 16 and the outer tube 17 are mounted on the base 11. The top cover 15 is fixed to the upper surface of the outer tube 17. A sealing gasket 6 is provided between the top surface of the outer tube 17 and the top cover 15 for sealing. A first inlet 111 is provided at the bottom of the inner tube 16; a first outlet 12 is provided on the side wall of the outer tube 17. The water tank 3 has a second outlet 31 at the bottom and a second inlet 32 ​​at the top. The water storage tank 4 has a third inlet 42 at the top and a third outlet 41 at the bottom. One end of the peristaltic pump 2 is connected to the first inlet 111 at the bottom of the fixed bed adsorption column 1 through a conduit 5. The other end of the peristaltic pump 2 is connected to the second outlet 31 of the water tank 3 through a conduit 5. The first outlet 12 of the fixed bed adsorption column 1 is connected to the third inlet 42 of the water storage tank 4 through a conduit 5. The upper and lower ends of the fixed bed adsorption column 1 are filled with quartz sand 13, and the middle of the fixed bed adsorption column 1 is filled with porous composite material 14.

[0017] The porous composite material 14 is a Zr-MOG / SA beads composite microsphere.

[0018] The preparation method of the Zr-MOG / SA beads is as follows:

[0019] 0.1726 g of ZrOCl2⋅8H2O and 0.1576 g of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine were dissolved in 1 mL of ethanol and 5 mL of dimethyl sulfoxide, respectively. The two solutions were mixed and sonicated until completely dissolved. The mixture was then transferred to a 120 °C drying oven and heated for 12 h. The resulting wet gel was dialyzed and then freeze-dried to obtain Zr-MOG powder.

[0020] Weigh out equal amounts of Zr-MOG powder and sodium alginate, dissolve them separately in water, mix the two solutions thoroughly, and then add them dropwise to a 1 wt% CaCl2 solution. Let stand for 12 hours, and wash with deionized water 3 to 4 times to obtain Zr-MOG / SAbeads.

[0021] Zr-MOG is a zirconium-based organometallic gel, and Zr-MOG / SA beads are zirconium-based organometallic gel / sodium alginate composite microspheres.

[0022] The working principle and process of this embodiment:

[0023] The methylene blue wastewater in the storage tank 3 enters the inner tube 16 of the fixed bed adsorption column 1 from the first inlet 111 through the peristaltic pump 2 at a constant flow rate. After passing through the adsorption zone composed of quartz sand 13 and porous composite material 14, the methylene blue is deposited on the surface of the adsorbent. The filtrate overflows from the inner tube 16 of the fixed bed adsorption column to the outer tube 17, and finally flows into the storage tank 4 from the first outlet 12 of the fixed bed adsorption column 1.

Claims

1. A double layer nested fixed bed device for removal of methylene blue, characterized by: The utility model relates to a fixed bed adsorption column, peristaltic pump, water inlet tank, water storage tank and conduit, the fixed bed adsorption column includes base (11), top cover (15), inner tube (16) and outer tube (17), the outer tube (17) is sleeved in the outer tube (16), the height of inner tube (16) is lower than the outer tube (17), and the inner tube (16) and outer tube (17) are all arranged on the base (11), the top cover (15) is fixed on the upper surface of outer tube (17), the top of outer tube (17) and top cover (15) between setting sealing rubber pad (6), the bottom of inner tube (16) is equipped with first water inlet (111), the outer tube (17) side wall is equipped with first water outlet (12), the lower part of water inlet tank (3) has second water outlet (31), the upper part of water inlet tank (3) has second water inlet (32), the upper part of water storage tank (4) has third water inlet (42), and the lower part of water storage tank (4) has third water outlet (41), one end of peristaltic pump (2) is connected with the first water inlet (111) of fixed bed adsorption column (1) lower end through conduit (5), the other end of peristaltic pump (2) is communicated with the second water outlet (31) of water inlet tank (3) through conduit (5), and the first water outlet (12) of fixed bed adsorption column (1) is communicated with the third water inlet (42) of water storage tank (4) through conduit (5), the upper and lower ends in the fixed bed adsorption column (1) are filled with quartz sand (13), and the middle in the fixed bed adsorption column (1) is filled with porous composite material (14).

2. A double nested fixed bed device for removal of methylene blue according to claim 1, characterized in that: The porous composite material (14) is Zr-MOG / SA beads composite beads.

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