Mechanochemical oxidation treatment method of ultraviolet absorbent UV-328

Abstract

The invention provides a mechanochemical oxidation treatment method of an ultraviolet absorbent UV-328, and belongs to the technical field of organic chemical solid waste treatment. According to the method, advanced oxidation and mechanochemical activation are coupled, and under the action of mechanical impact force and friction force, the oxidizing inorganic additive is activated to generate sulfate free radicals to mineralize and degrade UV-328. According to the method disclosed by the invention, through direct solid-phase reaction, no reaction solvent needs to be used, and the degradation and removal of organic chemical wastes are realized by depending on an advanced oxidation principle of mechanical energy activation, so that the limitation of an advanced oxidation technology based on solvent reaction on the dissolution requirement of organic matters is avoided; the reaction condition of the method is normal temperature and normal pressure reaction, external fuel heat energy input is not needed, mechanical energy is converted by civil electric energy, and the energy consumption cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of organic chemical solid waste disposal, and in particular to a mechanochemical oxidation disposal method of ultraviolet absorber UV-328. Background Art

[0002] Benzotriazole UV absorbers (BUVSs) are widely used in the field of polymer materials because they can effectively alleviate material photoaging and improve product stability. UV absorbers such as UV-328 (2-[2-hydroxy-3,5-di(1,1-dimethylpropylphenyl)]-2H-benzotriazole) and UV-329 are high-volume chemicals, but these UV absorbers have environmental persistence, easy migration and high biological toxicity. Among them, UV-328, as a typical benzotriazole UV absorber, may be restricted in the future. Therefore, it is of great significance to develop green and safe technologies that can efficiently dispose of organic chemicals.

[0003] At present, some studies have used advanced oxidation technology to degrade UV-328 in environmental media, but UV-328 has extremely poor water solubility and low environmental concentration (usually at the ng / L or μg / kg level). The treatment effect of degrading UV-328 in environmental media is minimal, and advanced oxidation technology based on solvent reactions is difficult to degrade high-purity organic chemicals. In addition, it is difficult to dispose of organic chemicals through biotechnology because microorganisms and plants are difficult to adapt to the toxicity of pure chemicals. Oxidative incineration is considered to be one of the effective means of disposing of waste and expired chemicals, but it faces problems such as high energy consumption, high cost, many secondary products, and large greenhouse gas emissions. At present, there is still a lack of effective methods for the green and safe disposal of UV-328 high-purity organic chemicals. Summary of the invention

[0004] The purpose of the present invention is to provide a mechanochemical oxidation treatment method for ultraviolet absorber UV-328, which can realize green and safe treatment of UV-328 high-purity organic chemicals.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a mechanochemical oxidation treatment method for ultraviolet absorber UV-328, comprising the following steps:

[0007] The oxidized inorganic additive, UV-328 and grinding balls are mixed and solid-phase ball milled to obtain a ball-milled material;

[0008] The oxidative inorganic additive includes potassium persulfate or potassium monopersulfate composite salt.

[0009] Preferably, the mass ratio of the oxidative inorganic additive to UV-328 is 30 to 50:1.

[0010] Preferably, the mass ratio of the grinding balls to the total mass of the oxidative inorganic additive and UV-328 is 30 to 60:1.

[0011] Preferably, the rotation speed of the solid phase ball mill is 400-450 r / min, and the diameter of the grinding balls is 5-8 mm.

[0012] Preferably, the total ball milling time is 60 to 120 minutes.

[0013] Preferably, the mass ratio of the oxidative inorganic additive to UV-328 is 40:1.

[0014] Preferably, the mass ratio of the grinding balls to the total mass of the oxidative inorganic additive and UV-328 is 50:1.

[0015] Preferably, when performing the solid phase ball milling, the ball mill runs for 10 minutes, stops for 1 minute, and then rotates in the reverse direction for 10 minutes.

[0016] Preferably, the ball milling jar and the grinding balls used in the solid phase ball milling are both made of zirconium oxide.

[0017] The present invention provides a mechanochemical oxidation treatment method for ultraviolet absorber UV-328. By coupling advanced oxidation and mechanochemical activation, under the action of mechanical impact and friction, the oxidative inorganic additive is activated to produce sulfate radical mineralization to degrade UV-328. The method of the present invention achieves degradation and removal of organic chemical wastes by direct solid phase reaction without using any reaction solvent, relying on the advanced oxidation principle activated by mechanical energy, and avoids the limitation of advanced oxidation technology based on solvent reaction on the dissolution requirement of organic matter; the reaction conditions of the method of the present invention are normal temperature and pressure reaction, no external fuel heat energy input is required, mechanical energy relies on civil electricity conversion, and energy consumption cost is low; the planetary ball mill equipment used in the present invention is modular, and system amplification and in-situ ex situ application can be easily achieved.

[0018] The present invention adopts suitable oxidizing inorganic additives, and can realize mechanical activation of inorganic solid reactants and degradation and removal of organic components through physical and chemical reactions induced by mechanical force through optimized mechanochemical operating parameters, thereby realizing efficient disposal of UV-328 by mechanochemical degradation.

[0019] Compared with the prior art, the present invention adopts mechanochemical oxidation method to treat UV-328, which is applicable to a wider range of ball milling operation parameters. Within the operating parameter range of material ratio of 30-50:1, ball-to-material ratio of 30-60:1, rotation speed of 400-450r / min, and grinding ball particle size of 6-8mm, the degradation rate of UV-328 can reach nearly 90%. The results show that when potassium persulfate (PDS) is selected as an inorganic additive, the degradation rate of UV-328 can reach 92.8% when the material ratio is 40:1, the ball-to-material ratio is 50:1, the rotation speed is 450r / min, the grinding ball particle size is 8mm, and the reaction time is 45min. The degradation rate of UV-328 can reach 94.89% when the reaction time is 120min. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The mechanochemical degradation effect of UV-328 after 120 min of reaction under the action of different inorganic additives;

[0021] Figure 2 The mechanochemical degradation effect of UV-328 with PDS as additive in different ball-to-material ratio systems;

[0022] Figure 3 The mechanochemical degradation effect of UV-328 with PDS as additive in different material ratio systems;

[0023] Figure 4 The mechanochemical degradation effect of UV-328 with PDS as additive under different rotation speed systems;

[0024] Figure 5 The mechanochemical degradation effect of UV-328 with PDS as additive and different grinding ball particle size systems;

[0025] Figure 6 The degradation effect of manual grinding of UV-328 with PDS or PMS as additive system. DETAILED DESCRIPTION

[0026] In the present invention, unless otherwise specified, the required raw materials or reagents are commercially available products well known to those skilled in the art.

[0027] The present invention provides a mechanochemical oxidation treatment method for ultraviolet absorber UV-328, comprising the following steps:

[0028] The oxidized inorganic additive, UV-328 and grinding balls are mixed and solid-phase ball milled to obtain a ball-milled material;

[0029] The oxidative inorganic additive includes potassium persulfate or potassium monopersulfate composite salt.

[0030] In the present invention, the oxidative inorganic additive includes potassium persulfate (K2S2O8, PDS) or potassium monopersulfate complex salt (2KHSO5·KHSO4·K2SO4, PMS).

[0031] In the present invention, the mass ratio of the oxidative inorganic additive to UV-328 is preferably 30 to 50:1, more preferably 40:1.

[0032] In the present invention, the mass ratio of the grinding balls to the total mass of the oxidative inorganic additive and UV-328 is preferably 30 to 60:1, more preferably 50:1.

[0033] The present invention preferably uses a planetary ball mill for solid phase ball milling, and the material of the ball milling jar and the grinding balls used in the solid phase ball milling is preferably zirconium oxide.

[0034] The present invention preferably mixes the oxidative inorganic additive, UV-328 and grinding balls in a ball mill, seals and fixes them on a planetary grinding disc, premixes them for 10 minutes at a rotation speed of 150 r / min, then officially runs the grinding disc at a revolution speed of 225 r / min, sets the ball mill rotation speed, and performs solid-phase ball milling.

[0035] In the present invention, the rotation speed of the solid phase ball mill (i.e., the rotation speed of the ball mill) is preferably 400-450 r / min, and the diameter of the grinding balls is preferably 5-8 mm, more preferably 6-8 mm; the present invention can select a combination of grinding balls of different diameters and adjust the mass ratio of grinding balls of different diameters as required for solid phase ball milling.

[0036] In the present invention, the total time of the ball milling is preferably 60 to 120 minutes.

[0037] In the present invention, when the solid phase ball milling is performed, the ball mill is operated for 10 minutes, stopped for 1 minute, and then rotated in the reverse direction for 10 minutes, so as to prevent overheating during the ball milling process.

[0038] In the present invention, in order to prevent the abrasive from agglomerating, the ball mill is operated in a horizontal manner.

[0039] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0040] Example 1

[0041] 4 g of inorganic additive (potassium persulfate, PDS), 0.1 g of UV-328 and 205 g of 8 mm diameter zirconia grinding balls were placed in a 250 mL zirconia ball mill of a planetary ball mill (the mass ratio of the inorganic additive to UV-328 (i.e., material ratio) was 40:1; the mass ratio of the grinding balls to the material (inorganic additive to UV-328) (i.e., ball-to-material ratio) was 50:1), sealed and fixed on a planetary grinding disc, pre-mixed for 10 min at a rotation speed of 150 r / min, the official operation grinding disc revolution speed was 225 r / min, the ball mill rotation speed was 450 r / min, the ball mill was operated in a horizontal manner for 10 min, stopped for 1 min, and then reversed for 10 min. The total ball milling operation time was 120 min to obtain a ball-milled material.

[0042] Example 2

[0043] The only difference from Example 1 is that the inorganic additive is potassium monopersulfate complex salt (PMS), and the rest is the same as Example 1.

[0044] Example 3

[0045] The only difference from Example 1 is that the ball-to-material ratio is 30:1, and the rest is the same as Example 1.

[0046] Example 4

[0047] The only difference from Example 1 is that the ball-to-material ratio is 40:1, and the rest is the same as Example 1.

[0048] Example 5

[0049] The only difference from Example 1 is that the ball-to-material ratio is 60:1, and the rest is the same as Example 1.

[0050] Example 6

[0051] The only difference from Example 1 is that the material ratio is 30:1, and the rest is the same as Example 1.

[0052] Example 7

[0053] The only difference from Example 1 is that the material ratio is 50:1, and the rest is the same as Example 1.

[0054] Example 8

[0055] The only difference from Example 1 is that the rotation speed of the ball mill is 400 r / min, and the rest is the same as Example 1.

[0056] Example 9

[0057] The only difference from Example 1 is that zirconia grinding balls with a diameter of 5mm+8mm and a mass ratio of 1:1 are used, and the rest is the same as Example 1.

[0058] Example 10

[0059] The only difference from Example 1 is that zirconia grinding balls with a diameter of 5 mm are used, and the rest is the same as Example 1.

[0060] Comparative Example 1

[0061] The only difference from Example 1 is that the inorganic additive is calcium oxide (CaO), and the rest is the same as Example 1.

[0062] Comparative Example 2

[0063] The only difference from Example 1 is that the inorganic additive is sodium sulfite (Na2SO3), and the rest is the same as Example 1.

[0064] Comparative Example 3

[0065] The only difference from Example 1 is that the material ratio is 20:1, and the rest is the same as Example 1.

[0066] Comparative Example 4

[0067] The only difference from Example 1 is that the rotation speed of the ball mill is 350 r / min, and the rest is the same as Example 1.

[0068] Comparative Example 5

[0069] The only difference from Example 1 is that the rotation speed of the ball mill is 500 r / min, and the rest is the same as Example 1.

[0070] Test Case

[0071] Extraction method of UV-328 in ball-milled materials obtained from different cases: accurately weigh 0.010 g of ball-milled materials, add 10 mL of ethyl acetate, vortex oscillate for 30 seconds, ultrasonically treat for 20 minutes, centrifuge at 4000 r / min for 5 minutes, take the supernatant, filter it through a 0.22 μm polytetrafluoroethylene membrane into a chromatographic bottle, and freeze it at -20°C for testing.

[0072] UV-328 measurement method in ball-milled materials: Liquid chromatography was used. The liquid chromatograph model was ThermoScientific UltiMate 3000, equipped with a UV-visible detector, and the chromatographic column model was Waters HSSC18 (5 μm×4.6 mm×250 mm) reverse phase chromatographic column, injection volume of 5 μL, isocratic elution, mobile phase of 100% methanol, flow rate of 1.0 ml / min, column temperature of 35°C, detection wavelength of 340 nm.

[0073] The degradation rate of UV-328 was calculated according to the following formula:

[0074] R(%)=n UV-328，t / nUV-328，0 ×100

[0075] D(%)=100-R(%)

[0076] Wherein, R is the residual rate of UV absorber UV-328, %; n UV-328,t is the amount of UV-328 in the mixed material at time t of ball milling reaction, mol; n UV-328,0 is the amount of UV-328 in the mixed material at the initial moment of ball milling reaction, mol; D is the degradation rate of UV-328, %.

[0077] Results Figures 1 to 5 , Figures 1 to 5 The vertical axis is the residual rate of ultraviolet absorber UV-328.

[0078] 1. Effect of additives on mechanochemical degradation of UV-328

[0079] Figure 1 The mechanochemical degradation effect of UV-328 after 120 minutes of reaction under the action of different inorganic additives; PDS and PMS are oxidizing additives, CaO and Na2SO3 are reducing additives, the material ratio is set to 40:1, the ball-to-material ratio is set to 50:1, the rotation speed is set to 450r / min, and the grinding ball particle size is selected to be 8mm. Figure 1 As shown, the degradation effect of oxidative additives is significantly better than that of reducing additives. UV-328 is an electron donor type organic matter that is more easily oxidized and degraded. The degradation effect of oxidative additive PDS is better than that of PMS. The system with PDS as an additive is dominated by sulfate radicals, and its oxidation ability is stronger than that of the PMS system dominated by direct oxidation. In addition, the cost of using PDS is much lower than that of PMS, and the environmental retention time of PDS is also longer than that of PMS.

[0080] 2. Mechanochemical degradation effect of UV-328 under different ball milling parameters

[0081] Figures 2 to 5 These are the mechanochemical degradation effects of UV-328 with PDS as additive at different ball-to-material ratios, different material ratios, different rotation speeds and different grinding ball diameters.

[0082] like Figure 2 As shown, when the ball-to-material ratio increases from 30:1 to 60:1 and the ball milling reaction lasts for 120 minutes, the degradation efficiency of UV-328 is greater than 85.0%. The degradation effect is best when the ball-to-material ratio is 50:1, reaching 94.89%. The degradation efficiency of UV-328 in the reaction system with a ball-to-material ratio of 60:1 slightly decreases to 93.27%, which is related to the self-quenching reaction of free radicals.

[0083] like Figure 3As shown, the degradation efficiency of UV-328 after ball milling reaction for 120 min varies greatly when the material ratio is from 20:1 to 50:1. When the material ratio is greater than 30:1, the degradation efficiency of UV-328 is greater than 92%. When the material ratio continues to increase to 50:1, the degradation effect is not significantly improved. Considering the reagent cost, the material ratio is selected as 40:1.

[0084] like Figure 4 As shown, the UV-328 degradation efficiency of the ball milling reaction for 120 minutes varies greatly when the rotation speed ranges from 350r / min to 500r / min. When the rotation speed is 400-450r / min, the UV-328 degradation efficiency can reach more than 85%. The lower rotation speed of 350r / min does not provide enough mechanical energy to activate PDS to produce active species to degrade organic matter. The higher rotation speed of 500r / min may lead to self-quenching of free radicals and inhibit the degradation effect.

[0085] like Figure 5 As shown, the grinding ball particle size is selected as 8mm, 5mm and the combined particle size of 8mm+5mm (the mass ratio of 8mm and 5mm grinding balls is 1:1), and the degradation rate of UV-328 can reach more than 93%. However, the grinding ball with a small particle size of 5mm is easy to induce material agglomeration during operation. In order to ensure the sustainable progress of the reaction, the grinding ball with a particle size of 8mm is selected.

[0086] 3. Degradation effect of UV-328 under manual grinding

[0087] With PDS or PMS as additive, the mixture of additive and UV-328 was manually ground in a mortar with a material ratio (mass ratio of additive to UV-328) of 40:1. The degradation effect is as follows: Figure 6 It can be found that the mechanical energy provided by manual grinding for 60 minutes is not enough to activate the additive and degrade UV-328, and there is a phenomenon of uneven materials in the grinding system, which increases the measurement error of the system.

[0088] In general, the mechanochemical ball milling reaction system used in the present invention can provide sufficient mechanical energy to activate the inorganic reagents to mineralize UV-328 and ensure the uniformity of the system.

[0089] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A mechanochemical oxidation treatment method for ultraviolet absorber UV-328, characterized in that: The following steps are involved: The oxidized inorganic additive, UV-328 and grinding balls are mixed and solid-phase ball milled to obtain a ball-milled material; The oxidative inorganic additive includes potassium persulfate or potassium monopersulfate composite salt.

2. The mechanochemical oxidation treatment method according to claim 1, characterized in that: The mass ratio of the oxidative inorganic additive to UV-328 is 30 to 50:

1.

3. The mechanochemical oxidation treatment method according to claim 2, characterized in that: The mass ratio of the grinding balls to the total mass of the oxidative inorganic additive and UV-328 is 30 to 60:

1.

4. The mechanochemical oxidation treatment method according to claim 3, characterized in that: The rotation speed of the solid phase ball mill is 400-450 r / min, and the diameter of the grinding balls is 5-8 mm.

5. The mechanochemical oxidation treatment method according to claim 4, characterized in that: The total time of the ball milling is 60 to 120 minutes.

6. The mechanochemical oxidation treatment method according to claim 2, characterized in that: The mass ratio of the oxidative inorganic additive to UV-328 is 40:

1.

7. The mechanochemical oxidation treatment method according to claim 3, characterized in that: The mass ratio of the grinding balls to the total mass of the oxidative inorganic additive and UV-328 is 50:

1.

8. The mechanochemical oxidation treatment method according to claim 5, characterized in that: When performing the solid phase ball milling, the ball mill runs for 10 minutes, stops for 1 minute, and then rotates in the reverse direction for 10 minutes.

9. The mechanochemical oxidation treatment method according to claim 8, characterized in that: The ball milling jar and the grinding balls used in the solid phase ball milling are both made of zirconium oxide.

Images