CN103523887B - Treatment method for glyphosate wastewater - Google Patents

Abstract

The invention discloses a treatment method for glyphosate wastewater. The treatment method for the glyphosate wastewater comprises the following steps: weighing 1.0000 g of a 95% glyphosate, then adding 100 mL of distilled water, dissolving in a beaker, then weighing accurately aluminum chloride according to the molar ratio of glyphosate to aluminum chloride of 1:4, adding into the beaker to dissolve, then adjusting the pH of the solution to be neutral by using sodium hydroxide, and stirring for 9 hours at the temperature of 30 DEG C; filtering, drying, carrying out suction filtration of the treatment liquid by a circulating water vacuum pump, and then putting the filter cake into an electric-heating constant-temperature air blast drying box for drying; measuring the volume of the treated filtrate, carrying out nitrosation, measuring by an ultraviolet spectrophotometer, and carrying out infrared spectroscopy detection of the dried filter cake; and measuring the content of organic pollutants. The recovery rate of glyphosate obtained by a metathesis reaction is high, and great contributions are made to implementation of energy-saving emission reduction and to realization of social economic sustainable development. In addition, the method disclosed by the invention is simple, effectively treats the glyphosate wastewater, and protects the environment.

Description

A kind of treatment method of glyphosate wastewater

technical field

The invention belongs to the technical field of wastewater treatment, in particular to a treatment method for glyphosate wastewater.

Background technique

At present, glyphosate production wastewater is an acidic wastewater containing high concentrations of inorganic salts and high concentrations of organic matter. The pollutants mainly include methanol, formaldehyde, and glyphosate. % of inorganic salts, such as sodium chloride (NaCl), therefore, at present, most production enterprises in our country add a certain amount of glyphosate dry powder and additives to make glyphosate with a mass fraction of 10% after concentrating the waste water Water agents are sold, but in this way, a large amount of inorganic salts and organic matter in the wastewater will be brought to the farmland, which will further cause soil compaction and salinization, as well as water pollution, so many researchers at home and abroad have done a lot of research The research work mainly adopts glyphosate wastewater treatment technologies such as physical chemical method, biological treatment method and combined process method.

The treatment methods of glyphosate production wastewater include hydrolysis, biochemical method, chemical precipitation method, chemical oxidation method, activated carbon adsorption method, resin adsorption method, advanced oxidation method, combined treatment method, membrane separation;

(1) chemical precipitation method

Xu Mingli and others studied the pretreatment and comprehensive utilization of glyphosate production wastewater. First, CaC12 solution was used as a precipitant to precipitate calcium salts from glyphosate. In this process, the recovery rate of glyphosate reaches 95%, and the removal rate of CODcr is greater than 95%, which fully realizes the comprehensive utilization of glyphosate wastewater. Liu Guoqing et al. Add alkali to neutralize the recovery catalyst in the glyphosate production wastewater, add excess calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, calcium salt or magnesium salt, and filter after sufficient reaction to obtain calcium salt or grass containing glyphosate The filter cake of magnesium salt of glyphosate, the filter cake is treated with inorganic acid to obtain glyphosate solution, the content of glyphosate and the content of COD in the filtrate are measured, and the recovery rate of glyphosate is 95%, and the COD removal rate is 95%. The removal rate of glyphosate is as high as 95%. Gao Fangfang et al. studied _the treatment and resource utilization of glyphosate combined with precipitation and metathesis recovery _. The removal rate of glyphosate is more than 95%. The recovery rate of glyphosate was 97.8%;

(2) Adsorption method

Adsorption is a low-energy solid-phase extraction separation method, which has been widely valued and applied to wastewater treatment processes. At present, many researchers at home and abroad are studying the separation of glyphosate and heavy metal ions, inorganic phosphate on various common adsorbents. The adsorption mechanism and adsorption model of ions, etc., for example: activated alumina has a good adsorption-desorption treatment effect on glyphosate, after using 10mL A1-1 alumina to adsorb and treat glyphosate wastewater, the removal rate of glyphosate reaches More than 98%, the COD removal rate reaches 50%, the maximum adsorption capacity of glyphosate by the activated carbon-loaded hydrated iron oxide adsorption method reaches 120mg/g, the adsorption capacity decreases with the increase of pH, and the phosphate radical inhibits the adsorption of AC-Fe significantly. Adsorption performance, Li Changhai, Li Zhenyu, Xiu Yanhua, etc. used D301R macroporous weakly basic anion exchange resin as the adsorbent, and the CODcr removal rate reached 96%, and it can effectively remove CLT acid in wastewater. Xiao Guqing et al. used 330 anion The research on the adsorption performance of exchange resin to glyphosate found that the adsorption effect was significantly reduced when the temperature was lowered, and the NaCl content increased;

(3) Chemical oxidation method

The chlorine dioxide oxidation method is to use hydrochloric acid to acidify the glyphosate mother liquor to adjust the pH value, then add sodium chlorate solution to react to obtain chlorine dioxide, and then chlorine dioxide oxidizes glyphosate and other organic substances to obtain a glyphosate decomposition rate of 70 %about;

The hydrogen peroxide oxidation method is to oxidize the glyphosate mother liquor with hydrogen peroxide, and further oxidize glyphosate and other organic substances, and obtain small molecules or inorganic substances through the oxidation of organic macromolecules. At this time, the decomposition rate of glyphosate reaches about 40%.

There are also high-temperature and high-pressure catalytic oxidation methods, ultraviolet oxidation methods with special wavelengths, etc.;

(4) Biochemical method

Cao Xiaoying et al. used a new type of anaerobic baffle reactor (ABR) to treat glyphosate wastewater. When the CODcr mass concentration of the raw wastewater was in the range of 6000-7000mg/L, the HRT of the reactor was set to 15-18h. , the removal rate of CODcr after treatment is 95.6%, and the removal rate of pollutants is as high as 95% or more;

(5) Advanced oxidation method

Liao Huan et al. used Fendon reagent to pretreat glyphosate wastewater, and finally obtained a total phosphorus removal rate of 95.7%, and a CODcr removal rate of 62.9%. The advantage of this method is that it can remove a large number of organic pollutants in glyphosate wastewater and alleviate In order to meet the pressure of subsequent biochemical treatment, Gu Yan et al. used Fendon photocatalytic method to degrade glyphosate wastewater, and used sunlight and ultraviolet light to degrade wastewater. At pH=3.0, n(H ₂ O ₂ ):n(Fe ²⁺ )=10 Under the condition of : 1, the COD removal rate is greater than 82%. In the experimental research on the utilization of useful components in glyphosate wastewater, Li Qihui and others adopted the Fenton-Mg(OH) ₂ method to process glyphosate wastewater. The degraded organic matter is treated with magnesium hydroxide adsorption and sedimentation, not only can effectively remove the organic matter, but also the COD removal rate can be as high as 76%. 3. When the reaction time is 30 minutes and the reaction temperature is 60°C, add 1.0mL H ₂ O ₂ (, 30%) and 0.25g FeSO ₄ ·7H ₂ O, the CODcr removal rate of glyphosate wastewater can reach 91.98%;

Dong Wengeng et al. in the study of sodium hypochlorite oxidation pretreatment of glyphosate production wastewater, obtained that in the original alkaline wastewater, the amount of sodium hypochlorite added is equivalent to 40% of the theoretical amount of available chlorine, and the reaction at room temperature for 4 hours, the removal rate of glyphosate can reach 98%. %;

(, 6) joint processing method

Zhang Huanzhen et al. used the selective bioreactor-UASB-CAAS combination process to treat the glyphosate wastewater pretreated by electrolysis. Firstly, the chloride ions were removed by electrolytic treatment, and then the selective bioreactor (UASB) and the upflow anaphylaxis were used. The oxygen sludge bed removes most of the organic pollutants (COD), and finally treats it with an anoxic-aerobic combined system (CAAS), and the COD removal rate reaches 99% after treatment;

Tang Jie et al. used a multi-dimensional electrocatalytic process to treat glyphosate mother liquor, and the COD removal rate reached about 85%, and the total phosphorus removal rate reached 90%;

(7) Membrane separation and concentration method

Membrane separation technology is an emerging technology in recent years. It is a new separation technology that separates mixtures, purifies and concentrates the target product through the selective permeability of the membrane.

The existing glyphosate wastewater treatment process has the problems of complicated operation, high treatment cost and poor efficiency.

Contents of the invention

The purpose of the embodiments of the present invention is to provide a treatment method for glyphosate wastewater, which aims to solve the problems of complicated operation, high treatment cost and poor efficiency in the existing glyphosate wastewater treatment process.

The embodiment of the present invention is achieved like this, a kind of treatment method of glyphosate waste water, the treatment method of this glyphosate waste water comprises the following steps:

Step 1, weigh 1.0000g of 95% glyphosate and add 100mL of distilled water, dissolve it in a beaker, then accurately weigh aluminum chloride, the molar ratio of glyphosate to aluminum chloride is 1:4, add it to the beaker for dissolution, Then use sodium hydroxide to adjust the pH of the solution to be neutral, and the stirring time at 30° C. is 9 hours;

Step 2, filtering and drying, using a circulating water vacuum pump to filter the treatment liquid, and then putting the filter cake into an electric heating constant temperature blast drying oven for drying;

Step 3, measuring the volume of the treated filtrate, performing nitrosylation, detecting with an ultraviolet spectrophotometer, and performing infrared spectrum detection on the dried filter cake;

Step four, test the content of organic pollutants.

Further, in step 2, the temperature of the electrothermal constant temperature forced air drying oven is set at 50°C.

Further, in step three, the specific method of glyphosate nitrosylation is:

Use a pipette to accurately draw 10 mL of the filtrate filtered with a filter head into a 100 mL volumetric flask, add 0.5 mL of sulfuric acid solution, 0.1 mL of potassium bromide solution, and 0.5 mL of sodium nitrite solution in sequence, quickly plug the stopper tightly, and shake well. Stand for 20 minutes, dilute to the mark with distilled water, shake well, open the stopper, let stand for 10 minutes, the nitrosation reaction temperature is greater than 15°C.

Further, the preparation of the sulfuric acid solution is as follows: the volume ratio of sulfuric acid and water is 1:1 to prepare a 50% sulfuric acid solution.

Further, the preparation of the sodium nitrite solution is as follows: 0.28g of sodium nitrite is weighed and dissolved in 20mL of distilled water.

Further, the preparation of the KBr solution is as follows: accurately weigh 25g of KBr and dissolve it in a 100mL volumetric flask.

Further, the specific method of step 4 is:

In the first step, take 5.00mL of glyphosate wastewater treatment solution and dilute it to 100mL;

In the second step, take 20.00mL of diluted water sample and place it in a 250mL ground-mouth reflux conical flask, weigh 0.4g of mercuric sulfate, add 10.00mL of potassium dichromate standard solution and several small glass beads or zeolites, and connect Ground spherical condenser tube, slowly add 30mL of sulfuric acid-silver sulfate solution from the top of the condenser tube, shake the Erlenmeyer flask gently to mix the solution evenly, and heat to reflux for 2h;

The third step, after cooling, slowly pour 90mL of distilled water from the top of the condenser tube, remove the Erlenmeyer flask, the total volume of the solution is not less than 140mL;

The fourth step, after the solution is cooled again, add 3 drops of ferrous ammonium indicator solution, and titrate with ferrous ammonium sulfate standard solution. The color of the solution changes from yellow to blue-green to reddish brown as the end point, and record the ferrous ammonium sulfate standard solution. dosage;

The fifth step, while measuring the water sample, take 20.00mL of distilled water, do a blank test according to the same operation steps, and record the amount of ammonium ferrous sulfate standard solution when measuring the blank;

Calculation formula:

CODcr(O ₂ , mg/L)=[(V ₀ -V1)×C×8×1000]/V

In the formula: C --- the concentration of ferrous ammonium sulfate standard solution;

V0 --- the amount of ammonium ferrous sulfate standard solution when titrating the blank;

V1 --- the amount of ammonium ferrous sulfate standard solution when titrating the water sample;

V---the volume of the water sample;

8 --- Oxygen (1/2O) molar mass.

Further, the preparation of potassium dichromate standard solution is as follows: dry potassium dichromate at 120°C for 2 hours until the quality remains unchanged, accurately weigh 3.0645g and dissolve it in water, transfer it into a 250mL volumetric flask, dilute to the standard line, and shake well;

The preparation of test ferrous spirit indicator solution is as follows: weigh 1.485g o-phenanthroline and 0.695g ferrous sulfate, dissolve in water, dilute to 100mL, and store in a brown bottle;

The preparation of ferrous ammonium sulfate standard solution is: weigh 39.5g of ferrous ammonium sulfate and dissolve it in water, slowly add 20mL of concentrated sulfuric acid while stirring, transfer it into a 1000mL volumetric flask after cooling, add water to dilute to the mark line, shake well, and use immediately Before, calibrate with potassium dichromate standard solution;

The preparation of sulfuric acid-silver sulfate solution is as follows: add 5g of silver sulfate to 500mL of concentrated sulfuric acid, leave it for 1-2d, and shake it from time to time to dissolve it;

Mercury sulfate is: crystal or powder.

Further, the specific method of potassium dichromate standard solution calibration is:

Accurately draw 10.00mL of potassium dichromate standard solution into a 250mL conical flask, add water to dilute to 110mL, slowly add 30mL of concentrated sulfuric acid, mix well, after cooling, add 3 drops of ferrous iron indicator solution to 0.15mL, use sulfurous acid Ferric ammonium solution titration, the color of the solution from yellow to blue-green to reddish brown is the end point,

C=0.2500×10.00/V

In the formula: C --- the concentration of ferrous ammonium sulfate standard solution;

V --- the amount of ferrous ammonium sulfate standard solution.

The treatment method of glyphosate wastewater provided by the present invention, the recovery rate of glyphosate obtained by metathesis reaction reaches 97.8%, and the adsorption effect is good. A large number of experiments have been carried out under conditions such as time and time, so as to determine the most reasonable composition ratio, operating conditions and the most reasonable method for the treatment of glyphosate wastewater, and achieve a good effect in the treatment of glyphosate wastewater. It has made a great contribution to decommissioning and achieving sustainable socio-economic development. In addition, the method of the invention is simple, easy to operate, effectively treats glyphosate wastewater, and protects the environment.

Description of drawings

Fig. 1 is the flowchart of the processing method of the glyphosate wastewater provided by the embodiment of the present invention;

Fig. 2 is the standard curve schematic diagram of the glyphosate provided by the embodiment of the present invention;

Fig. 3 is the schematic diagram of the molar ratio of glyphosate and aluminum chloride provided by the embodiment of the present invention;

Fig. 4 is the schematic diagram of the molar ratio that the embodiment of the present invention provides to glyphosate removal rate;

Fig. 5 is the schematic diagram of the influence of temperature on glyphosate removal rate that the embodiment of the present invention provides;

Fig. 6 is a schematic diagram of the influence of stirring time provided by the embodiments of the present invention on the glyphosate removal rate;

7 is a schematic diagram of the influence of molar ratios on CODcr provided by the embodiments of the present invention;

Fig. 8 is a schematic diagram of the influence of temperature on CODcr provided by the embodiment of the present invention;

Fig. 9 is a schematic diagram of the influence of stirring time on CODcr provided by the embodiments of the present invention;

Fig. 10 is a schematic diagram of the influence of sodium chloride provided by an embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Fig. 1 shows the process flow of the treatment method of glyphosate wastewater provided by the invention. For ease of illustration, only the parts relevant to the present invention are shown.

The treatment method of the glyphosate waste water of the embodiment of the present invention, the treatment method of this glyphosate waste water comprises the following steps:

Step 1, weigh 1.0000g of 95% glyphosate and add 100mL of distilled water, dissolve it in a beaker, then accurately weigh aluminum chloride, the molar ratio of glyphosate to aluminum chloride is 1:4, add it to the beaker for dissolution, Then use sodium hydroxide to adjust the pH of the solution to be neutral, and the stirring time at 30° C. is 9 hours;

Step 2, filtering and drying, using a circulating water vacuum pump to filter the treatment liquid, and then putting the filter cake into an electric heating constant temperature blast drying oven for drying;

Step 3, measuring the volume of the treated filtrate, performing nitrosylation, detecting with an ultraviolet spectrophotometer, and performing infrared spectrum detection on the dried filter cake;

Step four, test the content of organic pollutants.

As an optimization scheme of the embodiment of the present invention, in step 2, the electric heating constant temperature blast drying oven is set to 50°C.

As an optimization scheme of the embodiment of the present invention, in step 3, the specific method of glyphosate nitrosylation is:

Use a pipette to accurately draw 10 mL of the filtrate filtered with a filter head into a 100 mL volumetric flask, add 0.5 mL of sulfuric acid solution, 0.1 mL of potassium bromide solution, and 0.5 mL of sodium nitrite solution in sequence, quickly plug the stopper tightly, and shake well. Stand for 20 minutes, dilute to the mark with distilled water, shake well, open the stopper, let stand for 10 minutes, the nitrosation reaction temperature is greater than 15°C.

As an optimized solution of the embodiment of the present invention, the sulfuric acid solution is prepared as follows: the volume ratio of sulfuric acid to water is 1:1 to prepare a 50% sulfuric acid solution.

As an optimization scheme of the embodiment of the present invention, the sodium nitrite solution is prepared as follows: 0.28 g of sodium nitrite is weighed and dissolved in 20 mL of distilled water.

As an optimization scheme of the embodiment of the present invention, the preparation of the KBr solution is as follows: accurately weigh 25g of KBr and dissolve it in a 100mL volumetric flask.

As an optimization scheme of the embodiment of the present invention, the specific method of step 4 is:

In the first step, take 5.00mL of glyphosate wastewater treatment solution and dilute it to 100mL;

In the second step, take 20.00mL of diluted water sample and place it in a 250mL ground-mouth reflux conical flask, weigh 0.4g of mercuric sulfate, add 10.00mL of potassium dichromate standard solution and several small glass beads or zeolites, and connect Ground spherical condenser tube, slowly add 30mL of sulfuric acid-silver sulfate solution from the top of the condenser tube, shake the Erlenmeyer flask gently to mix the solution evenly, and heat to reflux for 2h;

The third step, after cooling, slowly pour 90mL of distilled water from the top of the condenser tube, remove the Erlenmeyer flask, the total volume of the solution is not less than 140mL;

The fourth step, after the solution is cooled again, add 3 drops of ferrous ammonium indicator solution, and titrate with ferrous ammonium sulfate standard solution. The color of the solution changes from yellow to blue-green to reddish brown as the end point, and record the ferrous ammonium sulfate standard solution. dosage;

The fifth step, while measuring the water sample, take 20.00mL of distilled water, do a blank test according to the same operation steps, and record the amount of ammonium ferrous sulfate standard solution when measuring the blank;

Calculation formula:

CODcr(O ₂ , mg/L)=[(V ₀ -V ₁ )×C×8×1000]/V

In the formula: C --- the concentration of ferrous ammonium sulfate standard solution;

V0 --- the amount of ammonium ferrous sulfate standard solution when titrating the blank;

V1 --- the amount of ammonium ferrous sulfate standard solution when titrating the water sample;

V---the volume of the water sample;

8 --- Oxygen (1/2O) molar mass.

As an optimization scheme of the embodiment of the present invention, the preparation of potassium dichromate standard solution is: Potassium dichromate is dried at 120 ℃ for 2h to constant quality, accurately weighs 3.0645g and dissolves in water, moves into 250mL volumetric flask, Dilute to the standard line, shake well;

The preparation of test ferrous spirit indicator solution is as follows: weigh 1.485g o-phenanthroline and 0.695g ferrous sulfate, dissolve in water, dilute to 100mL, and store in a brown bottle;

The preparation of ferrous ammonium sulfate standard solution is: weigh 39.5g of ferrous ammonium sulfate and dissolve it in water, slowly add 20mL of concentrated sulfuric acid while stirring, transfer it into a 1000mL volumetric flask after cooling, add water to dilute to the mark line, shake well, and use immediately Before, calibrate with potassium dichromate standard solution;

The preparation of sulfuric acid-silver sulfate solution is as follows: add 5g of silver sulfate to 500mL of concentrated sulfuric acid, leave it for 1-2d, and shake it from time to time to dissolve it;

Mercury sulfate is: crystal or powder.

As an optimized scheme of the embodiment of the present invention, the specific method of potassium dichromate standard solution calibration is:

Accurately draw 10.00mL of potassium dichromate standard solution into a 250mL conical flask, add water to dilute to 110mL, slowly add 30mL of concentrated sulfuric acid, mix well, after cooling, add 3 drops of ferrous iron indicator solution to 0.15mL, use sulfurous acid Ferric ammonium solution titration, the color of the solution from yellow to blue-green to reddish brown is the end point,

C=0.2500×10.00/V

In the formula: C --- the concentration of ferrous ammonium sulfate standard solution;

V --- the amount of ferrous ammonium sulfate standard solution.

The application principle of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the processing method of the glyphosate wastewater of the embodiment of the present invention comprises the following steps:

S101: Weigh 1.0000 g of 95% glyphosate, add 100 mL of distilled water, and dissolve in a beaker. Accurately weighed aluminum chloride, the molar ratio of glyphosate and aluminum chloride is 1:4, put into the beaker to dissolve, then adjust the pH of the solution to be neutral with sodium hydroxide, after that, at 30°C, stirring time for 9 hours;

S102: Filtration and drying, use a circulating water vacuum pump to filter the treatment liquid, and then put the filter cake into an electric heating constant temperature blast drying oven at 50°C for drying;

S103: measure out the volume of the treated filtrate, perform nitrosylation, detect with an ultraviolet spectrophotometer, and perform infrared spectrum detection on the dried filter cake;

S104: Test the content of organic pollutants;

The present invention is further described by following experiments:

Agilengt8453 ultraviolet spectrophotometer, Fourier transform infrared spectrometer, electronic balance (Shimaozu Corporation Japan), electric blast constant temperature drying oven 01-1 (Longkou Huangcheng Jingyi Electric Furnace Factory), glass instrument airflow dryer (Hualu Electric Heating Instrument Co., Ltd. ), circulating water vacuum pump (Henan Yuhua Instrument Co., Ltd.), electronic stirrer (manufactured by Jiangsu Jintan Medical Instrument Factory), filter device, magnetic heating stirrer 78-1 (Jiangsu Jintan Sunshine Instrument Factory), round Bottom flask, spherical condenser, precision thermometer, syringe, volumetric flask, glass rod, measuring cylinder, beaker, thermometer, acid burette, dropping bottle, pipette, ear ball, iron stand,

1. Experimental method

single factor test

Table 1 Single factor experimental design

① Accurately weigh 1.0000g of 95% glyphosate and add 100mL of distilled water to dissolve it in a beaker, then accurately weigh a certain mass of aluminum chloride and add it to the beaker to dissolve, then use sodium hydroxide to adjust the pH of the solution to be neutral, after that, At 30°C, the stirring time is 12 hours, stirring at a certain speed;

② Filtration and drying, use a circulating water vacuum pump to filter the treatment liquid, and then put the filter cake into an electric heating constant temperature blast drying oven at 50°C for drying;

③ Detection, measure the volume of the treated filtrate, and carry out nitrosylation, detect with an ultraviolet spectrophotometer, and carry out infrared spectrum detection on the dried filter cake;

④ Measure COD content;

Orthogonal experiment, the experimental design is as follows:

Table 2 Orthogonal experimental design

The steps are the same as the previous experiment,

The comparative experiment, the experimental design is as follows:

Table 3 comparative experimental design

Carry out under the condition that the mol ratio of glyphosate and aluminum chloride is 1: 4, experimental procedure is as previous experiment,

2 The method of glyphosate nitrosylation

(1) Preparation of solution

① Preparation of sulfuric acid solution: the volume ratio of sulfuric acid and water is 1:1 to prepare 50% sulfuric acid solution,

②Preparation of sodium nitrite solution: weigh 0.28g of sodium nitrite (accurate to 0.001g), dissolve it in 20mL of distilled water, and prepare the solution for immediate use.

③ KBr solution: Accurately weigh 25g KBr and dissolve it in a 100mL volumetric flask, (the service life of this series of solutions is within 20 days);

(2) Operation steps

Use a pipette to accurately draw 10 mL of the filtrate filtered by the filter head into a 100 mL volumetric flask, add 0.5 mL of sulfuric acid solution, 0.1 mL of potassium bromide solution, and 0.5 mL of sodium nitrite solution (prepared for current use) in sequence, and quickly put the plug into the Plug tightly, shake well, let stand for 20 minutes, dilute to the mark with distilled water, shake well, open the stopper, stand for 10 minutes, the nitrosation reaction temperature should not be lower than 15°C;

3. Determination of COD

(1) Preparation of solution

①Potassium dichromate standard solution (1/6K ₂ Cr ₂ O ₇ ): Pre-dry potassium dichromate at 120°C for 2 hours until the quality remains unchanged, accurately weigh 3.0645g, dissolve in water, transfer to a 250mL volumetric flask, dilute to the standard line, shake well;

② Ferrous test indicator solution: Weigh 1.485g o-phenanthroline (C ₁₂ H ₈ N ₂ ·H ₂ O), dissolve 0.695g ferrous sulfate (FeSO ₄ ·7H ₂ O) in water, dilute to 100mL, stored in a brown bottle;

③Standard solution of ferrous ammonium sulfate (Fe(NH ₄ ) ₂ (SO ₄ ) ₂ 6H ₂ O): Weigh 39.5g of ferrous ammonium sulfate and dissolve it in water, slowly add 20mL of concentrated sulfuric acid while stirring, and transfer to 1000mL of In the volumetric flask, add water to dilute to the marked line, shake well, and calibrate with potassium dichromate standard solution before use;

Calibration method: Accurately draw 10.00mL of potassium dichromate standard solution into a 250mL conical flask, add water to dilute to about 110mL, slowly add 30mL of concentrated sulfuric acid, mix well, and after cooling, add 3 drops of test ferrousin indicator solution (about 0.15 mL), titrated with ferrous ammonium sulfate solution, the color of the solution is the end point from yellow to blue-green to reddish brown,

C=0.2500×10.00/V

In the formula: C --- the concentration of ferrous ammonium sulfate standard solution (mol/L);

V --- the amount of ferrous ammonium sulfate standard solution (mL),

④Sulfuric acid-silver sulfate solution: add 5g silver sulfate to 500mL concentrated sulfuric acid, leave it for 1-2d, shake it from time to time to dissolve it,

⑤ Mercury sulfate: crystal or powder,

(2) Measurement steps

①Take 5.00mL of glyphosate wastewater treatment solution and dilute to 100mL;

②Take 20.00mL of diluted water sample and place it in a 250mL ground-mouthed reflux conical flask, weigh 0.4g of mercury sulfate, add 10.00mL of potassium dichromate standard solution and several small glass beads or zeolite accurately, and connect the ground-mouth Slowly add 30mL of sulfuric acid-silver sulfate solution from the top of the condenser tube, gently shake the conical flask to mix the solution evenly, and heat to reflux for 2 hours (timed from the beginning of boiling);

③ After cooling, slowly pour 90mL of distilled water from the top of the condenser tube, remove the Erlenmeyer flask, the total volume of the solution should not be less than 140mL;

④ After the solution is cooled again, add 3 drops of ferrous ammonium indicator solution and titrate with ferrous ammonium sulfate standard solution. The color of the solution changes from yellow to blue-green to reddish brown as the end point. Record the amount of ferrous ammonium sulfate standard solution;

⑤While measuring the water sample, take 20.00mL of distilled water, do a blank test according to the same operation steps, and record the amount of ferrous ammonium sulfate standard solution when measuring the blank;

calculate:

CODcr(O ₂ , mg/L)=[(V ₀ -V ₁ )×C×8×1000]/V

In the formula: C --- the concentration of ferrous ammonium sulfate standard solution (mol/L);

V0 --- the amount (mL) of ferrous ammonium sulfate standard solution when titrating the blank;

V1 --- the amount of ferrous ammonium sulfate standard solution (mL) when titrating the water sample;

V --- the volume of the water sample (mL);

8 --- Oxygen (1/2O) molar mass (g/mol),

4, glyphosate standard curve drawing, as shown in Figure 2,

(1) Preparation of standard sample solution: prepare a 1g/L solution and dilute it by 1.5 times, 2 times, 3 times, 4 times and 8 times respectively;

(2) Nitrosation: Accurately draw 10.00mL of the glyphosate standard solution and the six dilutions into six 100mL volumetric flasks with a pipette, and take another 100mL volumetric flask as a reagent blank. Add 0.5mL of sulfuric acid solution, 0.1mL of potassium bromide solution, and 0.5mL of sodium nitrite solution (ready-to-use), quickly plug the stopper, shake it well, let it stand for 20 minutes, dilute it with distilled water to the mark, shake it up, and open it. Put the stopper on for 15 minutes, and the nitrosation reaction temperature should not be lower than 15°C;

(3) measure the absorbance of a series of concentration glyphosate solutions with an ultraviolet spectrophotometer, obtain the calibration curve of glyphosate with absorbance to concentration mapping, fitting equation is: y=-0.02031+0.29033x, correlation coefficient R2= 0.99861 for analysis of glyphosate in sample solution;

5. The conclusion of the experiment:

single factor test

It can be seen from Figure 3 that with the decrease of the molar ratio of glyphosate to aluminum chloride, the removal of glyphosate in the treatment solution increases first and then decreases, and the molar ratio of glyphosate to aluminum chloride is 1:4 , the wastewater treatment effect is the best, this is because with the increase of aluminum chloride input, the amount of co-precipitation generated increases, and the removal rate of glyphosate will also increase, but when the input of aluminum chloride increases to 5 times, the removal rate of glyphosate decreases due to the salt effect and the same ion effect;

Orthogonal Test Result and Analysis of Glyphosate Removal Efficiency

In Table 4, it can be concluded from the P value that the molar ratio of glyphosate to aluminum chloride, temperature and stirring time have little effect on the removal rate of glyphosate, and it can be concluded from FC>FB>FA that each factor has a significant effect on the removal rate of glyphosate. The primary and secondary order of the removal rate of glyphosate: stirring time > temperature > molar ratio of glyphosate to aluminum chloride, for the molar ratio of glyphosate to aluminum chloride, K2>K1>K3, so glyphosate The mol ratio of phosphine and aluminum chloride is 1: 4 is the best level, the best level of the same temperature is 30 ℃, the best level of stirring time is 9 hours, thus, for the removal rate of glyphosate, The optimal solution is that the molar ratio of glyphosate to aluminum chloride is 1:4, the temperature is 30°C, and the stirring time is 9 hours;

Table 4 Orthogonal test analysis and results

variance analysis table

Note: F0.05(2, 2) = 19; F0.1(2, 2) = 9,

Effect of Molar Ratio on Glyphosate Removal Efficiency

It can be seen from Figure 4 that with the decrease of the molar ratio of glyphosate to aluminum chloride, the removal of glyphosate in the treatment solution increases first and then decreases. When the molar ratio of glyphosate to aluminum chloride is 1:4 , the wastewater treatment effect is the best, this is because with the increase of aluminum chloride input, the amount of co-precipitation generated increases, and the removal rate of glyphosate will also increase, but when the input of aluminum chloride increases to 5 times When , the removal rate of glyphosate decreased due to the influence of salt effect and common ion effect;

The effect of temperature on the removal rate of glyphosate

It can be seen from Figure 5 that as the temperature increases, the removal of glyphosate in the treatment solution first increases and then decreases. When the temperature is 30 °C, the removal rate of glyphosate is the best, because the reactant activity increases with the increase of temperature. If the temperature increases, the precipitation will increase, and the removal rate of glyphosate will increase. As the temperature increases from 30°C to 40°C, the reaction will release heat, which will cause the reaction balance to proceed in the opposite direction. At the same time, if the temperature is too high, the solubility will increase, which is not conducive to The adsorption of glyphosate reduces the removal rate of glyphosate;

The Effect of Stirring Time on Glyphosate Removal Efficiency

It can be seen from Figure 6 that at the beginning, with the prolongation of stirring time, the removal rate of glyphosate increases, the reason is that with the increase of time, the reaction is more complete, the precipitation particles are continuously reduced, the surface area is constantly increasing, and the adsorption capacity of glyphosate The reaction reaches equilibrium with increasing amount, but when the stirring time is 9-12 hours, the reaction has reached equilibrium, and the prolongation of the stirring time has no great influence on the removal effect of glyphosate, instead, the reaction may proceed in the opposite direction, and the removal effect reduce;

Orthogonal test results and analysis of CODcr removal rate

Table 5 Orthogonal test analysis and results

Variance analysis table

Note: F0.05(2, 2) = 19; F0.01(2, 2) = 9,

In Table 5, it can be concluded from the P value that the molar ratio of glyphosate to aluminum chloride, temperature and stirring time have little effect on the removal rate of COD, and it can be concluded from FA>FB>FC that each factor has a significant effect on the removal of COD The order of primary and secondary effects of efficiency: molar ratio of glyphosate to aluminum chloride>temperature>stirring time, for the molar ratio of glyphosate to aluminum chloride, K1>K2>K3, so glyphosate and chloride The molar ratio of aluminum is 1:3, which is the optimal level. Similarly, the optimal level of temperature is 40°C, and the optimal level of stirring time is 12 hours. Therefore, for the removal rate of COD, the optimal solution is glyphosate The molar ratio of phosphine to aluminum chloride is 1:3, the temperature is 40°C, and the stirring time is 12 hours.

Influence of the Molar Ratio of Glyphosate to Aluminum Chloride on the Removal Efficiency of CODcr

It can be seen from Figure 7 that with the increase of the addition of aluminum chloride, the removal rate of CODcr decreases continuously. The reason may be that with the increase of the addition of aluminum chloride, the amount of sodium hydroxide also increases, and the presence of A large amount of Na+, Cl+, CODcr also increases with the increase of inorganic salts in the solution;

Effect of temperature on the removal rate of CODcr

It can be seen from Figure 8 that with the increase of temperature, the removal rate of CODcr also increases slightly, but overall, the effect is not significant;

Effect of stirring time on the removal rate of CODcr

It can be seen from Figure 9 that with the prolongation of the stirring time, the removal rate of CODcr also increases slightly. The reason may be that the amount of miscellaneous ions and impurities in the solution adsorbed on the precipitate continues to increase. However, there may be relatively large errors in the measurement of COD , and the overall effect is not significant;

The effect of sodium chloride

When the molar ratio of glyphosate to aluminum chloride is 1:4, the temperature is 30°C, and the stirring time is 9 hours,

Table 6 Effect of Sodium Chloride

It can be seen from Figure 10 that with the increase of sodium chloride addition, the removal rate of glyphosate decreases slightly, but the reduction is not large; the removal rate of COD increases significantly;

6. Summary

(1) By single factor test, the influence of the molar ratio is V-type, that is, the glyphosate removal effect first improves with the decrease of the molar ratio of glyphosate and aluminum chloride; until the molar ratio is 1: 4, the treatment effect is the best; after that, it decreases with the decrease of the molar ratio;

(2) Through the orthogonal test, it can be known that the removal rate of glyphosate is the best when the molar ratio of glyphosate to aluminum chloride is 1:4, the temperature is 30°C, and the stirring time is 9 hours, and the three Factors have little effect on the removal rate of glyphosate;

(3) Through the orthogonal test, it can be seen that the removal rate of CODcr is the best when the molar ratio of glyphosate to aluminum chloride is 1:3, the temperature is 40°C, and the stirring time is 12 hours, and the removal rate of glyphosate and chlorine is the best. The molar ratio of Al2 has the most significant effect;

(4) Through comparative experiments, it can be seen that the addition of sodium chloride has no significant effect on the removal rate of glyphosate, but the removal rate of COD increases gradually with the addition of sodium chloride.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (1)

1. a treatment process for glyphosate waste water, is characterized in that, the treatment process of this glyphosate waste water comprises the following steps:

Step one, claims the glyphosate of 1.0000g 95% to add the distilled water of 100mL, is dissolved in beaker, take aluminum chloride again, the mol ratio of glyphosate and aluminum chloride is 1: 4, adds in beaker and dissolves, then being neutral with the pH of sodium hydrate regulator solution, is 9 hours 30 DEG C of churning time;

Step 2, filters, dries, and uses vacuum pump using circulatory water that treatment solution is carried out suction filtration, then filter cake is put into electric heating constant-temperature blowing drying box dries;

Step 3, measures volume by the filtrate processed, and carries out nitrosylation, detects, and filter cake complete for drying is carried out infrared spectra detection with ultraviolet spectrophotometer;

Step 4, the content of test organic pollutant;

In step 2, electric heating constant-temperature blowing drying box is set to 50 DEG C;

In step 3, the concrete grammar of glyphosate nitrosylation is:

With transfer pipet accurately the filtrate 10mL that filters of absorption filter in 100mL volumetric flask, add 0.5mL sulphuric acid soln, 0.1mL potassium bromide solution, 0.5mL sodium nitrite solution successively, rapidly by stopper jam-pack, fully shake up, place 20min, with distilled water diluting to scale, shake up, open stopper, place 10min, nitrite acidizing temperature of reaction is greater than 15 DEG C;

Being formulated as of sulphuric acid soln: the volume ratio of sulfuric acid and water is 1: 1 sulphuric acid soln being mixed with 50%;

Being formulated as of sodium nitrite solution: take 0.28g Sodium Nitrite, is dissolved in 20mL distilled water;

Being formulated as of KBr solution: take 25gKBr and be surely dissolved in 100mL volumetric flask.