CN102941223A

CN102941223A - Ultraviolet ozone processing method for residual pesticide in rice field soil

Info

Publication number: CN102941223A
Application number: CN2012104854045A
Authority: CN
Inventors: 史忠科; 山丹
Original assignee: Xian Feisida Automation Engineering Co Ltd
Current assignee: Xian Feisida Automation Engineering Co Ltd
Priority date: 2012-11-25
Filing date: 2012-11-25
Publication date: 2013-02-27

Abstract

The invention provides an ultraviolet ozone processing method for residual pesticide in rice field soil. The method is applicable for long-term water-logging oxygen deficit environment of the rice field soil. Ultraviolet is used for lighting an ozone aqueous solution, under the lighting of ultraviolet, ozone is decomposed into hydroxyl radicals with strong oxidizing property, the hydroxyl radicals conduct photocatalytic oxidation on the rice field soil, and the ozone solution generated through the method is adopted in an early stage of irrigation for rice field soil to conduct pre-processing in a method of ploughing-irrigating-dewatering. The technical defect in the existing residual pesticide processing method that activity is limited, stabilization is poor and secondary pollution is easy to cause is overcome. The technical purpose of processing residual pesticide in the long-term water-logging oxygen deficit environment of the rice field soil is solved.

Description

A kind of UV ozone processing method of paddy soil remains of pesticide

Technical field

The present invention relates to a kind of UV ozone processing method of paddy soil remains of pesticide, the method is irrigated pending soil by the ozone water solution of UV-irradiation, makes the oxidized decomposition of remains of pesticide in the soil, belongs to environmental protection technical field.

Background technology

The paddy soil remains of pesticide can cause serious harm to development and the environmental protection of agricultural economy, residues of pesticides are adsorbed on can be to soil property in the soil particle, biological, the aspects such as crops work the mischief, aspect soil property, the soil of long-term pollution is acidification, nutrient (nitrogen in the soil, phosphorus, potassium etc.) can reduce along with increasing the weight of of pollution level, soil porosity diminishes, cause soil texture to harden, aspect biological, residual in soil of agricultural chemicals will be to the microorganism in the soil, protozoan, arthropod, annelid and round worm etc. produce harm, destroy the ecosystem, aspect crops, the agricultural chemicals that remains in the soil can have a negative impact to crop growth, and pesticidal toxin is accumulated in crops, final progressively enrichment through food chain enters human body and causes slow poisoning, and health is threatened; Paddy soil distributes very wide in China; account for more than 25% of national cultivated area; paddy soil is different from common agricultural land soil; to plough slaking, waterflooding kind rice and the anthropogenic soil that forms through artificial water; characteristic with long-term water logging anoxic; bacterial micro-organism more easily grows; insect pest is more serious; the agricultural chemicals use amount is large; and do not have at present a kind of effectively for the pesticide-treated method of paddy soil characteristic; therefore, a kind of UV ozone processing method of paddy soil remains of pesticide has great significance in agricultural and field of environment protection.

Existing Pesticide-Polluted Soil processing method mainly contains biological decomposition method, physical treatment process, method of chemical treatment, oxidation Decomposition method etc.; The existing mechanism of action of biological decomposition method is mainly the mode of bacterial metabolism, the essence of bacterial degradation agricultural chemicals is enzymatic reaction, operation principle is that compound enters in the bacterial body by certain mode, then under the effect of various enzymes, through a series of biochemical reactions, agricultural chemicals is degradable or resolve into the process of the nontoxic of molecular weight or the compound that toxicity is less the most at last, but digestive enzyme easily is subjected to abiotic sex change in soil, the effects such as adsorption by soil and inactivation, be difficult to keep for a long time degrading activity, and the poor mobility of enzyme in soil, this has all limited the application of biological treatment in the pedo relict pesticide-treated; Physical treatment process can be divided into two kinds of extraction and absorption methods, extraction claims again liquid-liquid extraction method, it is the isolation technics of a kind of extraction from the aqueous solution, separation and enrichment utility, absorption method is to adopt different adsorbents, the adsorption capacity that common are diatomite, gelatin, active carbon, resin etc. shifts from soil, the physics ratio juris is that insecticide pollution is transferred to other phase from the aqueous phase of soil water solution, does not realize the processing of agricultural chemicals, still can produce harm to environment; Chemical treatment method adopts and to add alkali, chlorination, add the method such as hypochlorite and with agricultural chemicals chemistry reflection destruction decomposing pesticide occurs, but some agricultural chemicals stable in properties, to be difficult for biodegradable intractable compound, the pesticide variety that the method is processed is limited, and the chemical reagent that adopts is in decomposing pesticide, can produce the accessory substance of environmental pollution, environment is damaged; The oxidation Decomposition method mainly adopts the mode of ozone oxidation, because ozone has strong oxidizing property, can with most of agricultural chemicals generation redox reactions, be nontoxic compound with poisonous agricultural chemicals oxidation Decomposition, and ozone self decomposes generation oxygen, can not work the mischief to environment, but the solubility of ozone in water is very little, directly that oxidation efficiency in the ozone passage paddy soil is very low.

Patent " Chen Youming. the method [P] of the water-soluble improvement soil of a kind of ozone. China: CN101607261A.2009-12-23 " method that the water-soluble irrigation soils of a kind of ozone are processed residues of pesticides proposed, the method with ozone by water-gas mixer and gas-liquid mixing pump, the Ozone Water that water is mixed in 2-8PPM concentration is irrigation soils immediately, repeat 2-6 time, reach the purpose of processing residues of pesticides, it is inhomogeneous that the Ozone Water irrigation technique that the method adopts exists ozone to mix with soil, ozone utilization rate is low, to the deep soil poor processing effect, cause the shortcoming of water resource waste, and ozone solubility in water is low, easily be decomposed into oxygen, be not suitable for the paddy soil environment with long-term water logging anoxic.

In sum, there is poor activity, perishable in existing Pesticide-Polluted Soil processing method, the processing pesticide variety is few, environment is produced the shortcomings such as serious secondary pollution, and existing processing method can not solve the technical problem that remains of pesticide is processed in this long-term water logging anaerobic environment of paddy soil mainly for normal soil.

Summary of the invention

Can not be applicable to the technical problem of this long-term water logging anaerobic environment of paddy soil in order to solve existing remains of pesticide processing method, the present invention proposes a kind of UV ozone processing method of paddy soil remains of pesticide, environment for this long-term water logging anoxic of paddy soil, adopt the ultraviolet lighting ozone water solution, utilize under the ultraviolet lighting ozone in water, to be decomposed into the hydroxyl radical free radical with strong oxidizing property the paddy soil that is subjected to pollution by pesticides is carried out photochemical catalytic oxidation, carry out preliminary treatment in the paddy soil mode that the ozone water solution that adopts this mode to generate early stage carries out "---irrigation---draining of turning over " of pouring water, can overcome existing remains of pesticide processing method exists active limited, poor stability, easily produce the technological deficiency of secondary pollution, solve the technical problem that this long-term water logging anaerobic environment remains of pesticide of paddy soil is processed.

The present invention solves this technical problem the technical scheme that adopts: a kind of UV ozone processing method of paddy soil remains of pesticide mainly comprises following characteristics:

1, ozone farthest is decomposed into the hydroxyl radical free radical OH with strong oxidizing property in water under the 245nm ultraviolet lighting, and reaction equation is shown below:

Set up a relational expression according to above-mentioned reactional equation: under the condition of wavelength 245nm ultraviolet lighting, 1mol ozone decomposes in water fully can generate the 2mol hydroxyl radical free radical;

2, before rice transplanting, adopt the mode of "---irrigation---draining of turning over " to carry out the remains of pesticide processing, the purpose of turning over is that the ozone water solution that contains hydroxyl radical free radical can fully be contacted with deep soil, because the paddy soil residues of pesticides have in the soil that all concentrates on upper soll layer 0 ~ 400mm degree of depth more than 95%, select ploughed depth greater than 300mm less than 400mm, can impel the remains of pesticide more than the hydroxyl radical free radical and 95% in the ozone water solution fully to react, by this ozone water solution of rear venting that reacts completely of the processing time shown in the pollution condition shown in the table 1 classification processing list, can reduce the impact that residual hydroxyl radical pair plant growth causes;

3, according to the difference of contaminated paddy rice soil contamination grade, the selection hydroxy free radical concentration is that the ozone water solution of 0.5 ~ 2g/L carries out " turning over-irrigate-draining " processing mode, and the amount of irrigating the ozone water solution that uses is 100L/m2, provides according to table 1

Table 1 pollution condition classification processing list

Pollution condition classification and irrigation method carry out.

The invention has the beneficial effects as follows: owing to adopting the ultraviolet lighting ozone water solution, ozone is decomposed into the hydroxyl radical free radical with strong oxidizing property the paddy soil that is subjected to pollution by pesticides is carried out photochemical catalytic oxidation in water, paddy soil pour water the early stage adopt this ozone water solution to carry out "---irrigation---draining of turning over " mode process, can overcome existing remains of pesticide processing method and have active limited, poor stability, easily produce the technological deficiency of secondary pollution, solve the technical problem that existing remains of pesticide processing method can not be applicable to this particular surroundings of paddy soil.

Below in conjunction with embodiment the present invention is elaborated.

The specific embodiment

Being treated to example with the Furadan residual contamination describes.

1. Furadan has another name called carbofuran (C ₁₂H ₁₅NO ₃Molecular weight 221.38) is a kind of carbamate chemicals for agriculture commonly used, has quick-acting good, acting duration is long, various agricultural insect virus there are the characteristics of pretending usefulness, thereby be widely used in the modern agriculture field, be subjected to the paddy soil of Furadan residual contamination to carry out experimental study to one, (paddy soil of 1m * 1m) is as the experimental plot to select surface area wherein to be 1 square metre, adopt first plough that this piece soil is turned over before the irrigation, ploughed depth is about 30mm, and purpose is the contact area that increases between pending soil and the ozone water solution;

2. the Furadan concentration that at first records in this soil by gas chromatography is 0.479mg/kg, and the density of general soil is at 2.6～2.8g/cm ³The content that can calculate residual Furadan in this piece experimental plot is about 0.002mol, suppose not consider other remains of pesticide, belong to slight pollution in this piece experimental plot as can be known according to table 1, the preparation hydroxy free radical concentration is the ozone water solution 100L of 0.5g/L under the ultraviolet lighting of wavelength 254nm, calculating obtains wherein, and the content of hydroxyl radical free radical is about 2.94mol, enough with the Furadan complete oxidation in this piece experimental plot, the unnecessary reaction solution of venting behind the irrigation processing 150min, reduce residual hydroxyl free radical and ozone to the impact of plant growth, other remains of pesticide course of reaction principle is similar, describes no longer separately.

3.150min after, adopt gas chromatography to record the content of Furadan less than 0.001mg/kg to this piece experimental plot, therefore the method more than 99.7%, can effectively solve the technical problem that this particular surroundings residues of pesticides of paddy soil are processed to the treatment effeciency of remains of pesticide Furadan in this piece experimental plot.

Claims

1. the UV ozone processing method of a paddy soil remains of pesticide mainly comprises following characteristics:

(1) ozone farthest is decomposed into the hydroxyl radical free radical OH with strong oxidizing property in water under the 245nm ultraviolet lighting, and reaction equation is shown below:

(2) before rice transplanting, adopt the mode of "---irrigation---draining of turning over " to carry out the remains of pesticide processing, the purpose of turning over is that the ozone water solution that contains hydroxyl radical free radical can fully be contacted with deep soil, because the paddy soil residues of pesticides have in the soil that all concentrates on upper soll layer 0 ~ 400mm degree of depth more than 95%, select ploughed depth greater than 300mm less than 400mm, can impel the remains of pesticide more than the hydroxyl radical free radical and 95% in the ozone water solution fully to react, by this ozone water solution of rear venting that reacts completely of the processing time shown in the pollution condition shown in the table 1 classification processing list, can reduce the impact that residual hydroxyl radical pair plant growth causes;

(3) according to the difference of contaminated paddy rice soil contamination grade, the selection hydroxy free radical concentration is that the ozone water solution of 0.5 ~ 2g/L carries out " turning over-irrigate-draining " processing mode, and the amount of irrigating the ozone water solution that uses is 100L/m2, according to table 1

Table 1 pollution condition classification processing list

The pollution condition classification and the irrigation method that provide carry out.