I. Introduction Antimony (Antimony), atomic symbols Sb, which is derived from the Latin name stibium, element belonging to group Ⅴ first main group, atomic number 51. Antimony is a noble metal gender, total valence of four (-3,0, + 3, + 5), the latter two primary valence environment. Antimony fouling environment from two parts: an artificially contaminated coal combustion which portion comprises antimony-containing waste, dust caused by mining operations, waste water, waste, and the power plant of gasoline used antimony-containing fuel. 2. Natural pollution, which mainly refers to the phenomenon of high strontium content in the surrounding environment due to its special geological conditions in the enriched areas such as Yankuang, and some hot springs and geothermal areas. Nriagu et al. pointed out that anthropogenic pollution is much more serious than natural pollution. Affected by factors such as weathering of rocks, scouring of rainwater and anthropogenic emissions, natural waters will eventually become the home of most cockroaches. The hydrazine is present in the aqueous environment in the form of various compounds or in a suspended state or in a dissolved state. Some studies have shown that earthworms are chronically toxic and carcinogenic to organisms and humans. The problem of pollution can not be ignored. The pollution and its distribution and toxicity in the environment have been reported in foreign countries. Based on the review of domestic and foreign literatures, this paper reviews the various removal methods of strontium in water, and provides reference for the treatment and research of strontium pollution. Second, the toxicity and environmental standards of cockroaches It is not an essential element of the organism. The order of 锑 toxicity of different valence states is as follows: 0 valence > +3 (III) valence > + 5 (V) valence > organic hydrazine. Among them, the toxicity of trivalent europium is ten times higher than that of pentavalent. Based on the toxicity study of cockroaches, some scholars have obtained the maximum allowable concentration of strontium in soil of 3.5 - 5 mg / kg. The US Environmental Protection Agency and the European Union listed 锑 as a priority pollutant in 1979 and 1976, respectively, and the Japanese Environmental Protection Agency also listed it as a closely watched pollutant [7] . All countries in the world have set strict environmental standards for them. Germany stipulates that the average daily sucking volume of the human body is 23 μg Sb/d. The European Union specifies a maximum allowable concentration of cesium in drinking water of 5 μg/L. Japan has a specification of 2 μg/L. The US Environmental Protection Agency has set the MCLG (maximum contaminant level goal) and MCL (maximum contaminant level) values ​​in drinking water to 6 μg/L. Based on the 0.43 mg/(kg.d) pathogenic strontium observed in house mice, the World Health Organization stipulates that the strontium content in drinking water should be less than 5 μg/L. China has also made corresponding limits on the environment in the country. China's "surface water environmental quality standards" (GB3838-2002) and "Sanitary Standards for Drinking Water" (Ministry of Health, 2001) have set the limit of 锑 to 5μg / L. The “Code for Planning of Urban Water Supply Projects†(GB50282-98) stipulates that 水<10 μg/L in the effluent of water plants, and also 锑<50 μg/L in drinking water sources. 3. Valence, morphology and reaction of earthworms in natural waters (1) Analysis methods and instruments Effective, rapid and sensitive detection and analysis methods are necessary conditions for studying the morphology, migration and transformation of earthworms in the environment, and there are many related researches and literatures. With the efforts of researchers and the continuous improvement of analytical methods, the valence analysis of cesium (that is, the analysis of strontium content in different valences in samples) already has a relatively mature theory and method. At present, commonly used valence analysis methods include spectrophotometry, electrochemical analysis, and atomic spectroscopy. With the improvement of enrichment and separation methods, atomic fluorescence spectrometry, hydride generation inductively coupled plasma mass spectrometry (HG-ICP-MS), hydride generation inductively coupled plasma atomic emission spectrometry (HG-ICP-AES), etc. The new method has reached a satisfactory detection limit in valence analysis. In 1981, Andreaa introduced a chromatographic method for the analysis of ruthenium. Using hydride generation gas chromatography atomic absorption spectroscopy (HG-GC-AAS), MSA ((CH 3 )SbO(OH) 2 ) and DMSA (( CH 3 ) 2 SbO(OH)). Using chromatographic and elemental feature detectors, not only can cesium of different valence states be analyzed, but also various alkyl hydrazine compounds (currently methyl hydrazine) can be separated and determined according to the chromatographic behavior of different organic compounds, and the morphology of unknown strontium can be predicted [14] ] . However, the detection limit for the detection of inorganic hydrazine by a combination of chromatographic and elemental feature detectors is currently not ideal. In short, due to the lag of the morphological analysis methods of cockroaches, countries around the world can only establish corresponding environmental standards for the total cockroaches, and cannot make more detailed regulations based on the toxicity of different valence compounds. (2) Hydrolysis of cerium ions The cerium ions are mainly present in the water at trivalent or pentavalent. Simple antimony compound is very low solubility in water: Sb 2 O 3 solubility at 100 ℃ is parts per million, at room temperature is lower, which Ksp = 1.5 × 10 - 93; Sb 4 O 6 is at room temperature Two ten thousandths [15] . Probably because of the extremely low solubility, there are few records about the hydrolysis reaction constant of hydrazine in the literature, but mainly the mechanism and influencing factors of the valence distribution of different valence states in water. The current consensus in academia can be summarized as [16] : 1. The trivalent europium ion exists as a neutral molecule (Sb(OH) 3 or SbO(OH) or HsbO 2 ) in a wide pH range (about 2 to 10), and exists in the form of SbO + or Sb in a strong acid environment. (OH) 2 +, the alkali environment is SbO 2 - or Sb (OH) 4 -, Sb 3 + free form may only be present in the extreme acidic environments. 2. Pentavalent cerium ions exist in the form of Sb(OH) 6 - or SbO 3 - in the weak acid, neutral and alkaline range, and exist in the form of SbO 2 - under strong acid conditions. 3. Based on thermodynamic experiments, the following theoretical relationship exists between the conversion of two valence states: According to the above formula, in the oxygen-rich water (such as surface water), the content of trivalent europium should be almost no, but mainly in the form of pentavalent barium, and vice versa. In fact, however, it has been found that not only trivalent europium can exist in some oxygen-rich environments, but also pentavalent anthracene can also occur in anoxic environments. The reason is because the physical and chemical environment in the actual water body is more complicated. In addition to dissolved oxygen, sediments, organisms and suspended particles may have an effect on the morphology of the earthworm. In general, surface water is still the most pentad. 4. There are few reports on the polymerization of cesium. In a strong alkaline environment, there may be a polymeric ion of pentavalent europium. Scholder et al hypothesize that there Sb 6 O 10 2 at 0.1 ~ 0.01mol / L sodium hydroxide solution - and Sb 4 O 7 2 -. (3) Reaction of cerium ions with simple ions It has a strong sulfophilicity and is mainly present in the form of sulfides, namely Sb 2 S 3 , in nature. Halogenated antimony in industrial production is also more common. Therefore, most of the literature focuses on the reaction of chloride, sulfur and strontium ions in solution. Studies have shown that both ions can form various polymeric ions with hydrazine; Sb(III) is soluble in concentrated HCl, and the compound formed with chlorine can be described by the general formula SbCl x [(x - ) + 3] + , In the presence of excess water, chlorine can also form SbOCl insolubles with trivalent europium; there are few studies on Sb(V) chloride, and Fridman gives its general formula SbCL x [(x - ) + 5] based on the adsorption data . + . Further, rhodium may be dissolved in an alkaline solution (e.g., dissolved in Na 2 S), or an amorphous sulfide compound Sb 2 S 3 (acidic) or SbS 2 (alkaline) may be formed. It should be noted that almost all studies on chloride and hydrazine reactions are carried out in a strong acid environment. When the sulfur ions react with hydrazine, the concentration of sulfur is also relatively large. In natural waters, the ionic strength, the diversity of impurities, and the pH value are far from the water samples prepared in the laboratory. Therefore, whether the chlorine or sulfur ions in the actual water body react with strontium and the reaction mechanism are still not clear. . (4) Reaction of cerium ions with organic matter Antimony (III) may contain a range of O - Mapping and S - is an organic ligand complex, may be soft and coordinating ligands, such as SH ligands may be ligands with coordinating hardware, such as -COOH with It can also be chelated with CDTA, DTPA, EDTA, etc. And the pentavalent quinone can only be complexed with a few organic ligands. Their complexation properties are used in the field of analysis as a means of efficient and selective separation. The reaction between natural organic matter and earthworms has rarely been reported. In 1995, Pilarski found that humic acid can adsorb barium tartrate and Sb(OH) 3 , and its adsorption isotherm follows the Langmuir equation, while humic acid has little adsorption to pentavalent barium. He also speculated that it may be due to the pentavalent strontium ion in the form of a negatively charged acid group of SbO 3 - , and the humic acid is also negatively charged in water. (5) Adsorption of cerium ions on solid particles If the water is in the majority of the pentavalent strontium ions, since the suspended particles and sediments in the water are mostly negatively charged, they will not adsorb the negatively charged SbO 3 - . The results of Jarvie [19] and Stordal et al. confirm the above hypothesis. Tanizaki et al. conducted a more specific demonstration. They used a 0.45um filter to filter some river water. It was found that about 70% of the "dissolved" ruthenium could be filtered through the membrane, and the molecular mass of these mites was found. Below 500 Da, it is speculated that the presence of ruthenium is Sb(OH) 6 - . Brannon and Patrick found that most of the strontium in the anoxic soil containing 0.5 to 17.5 ug/g contained a combination of stable iron and aluminum oxide. Domestic He Mengchang and others also found cockroach pollution in the soil around the mining area. However, they did not give clear conclusions about the price and form of the cockroaches. Crecelius etc. In investigating the vicinity of a copper mineral soil antimony found that <20% of antimony is combined with iron and aluminum compounds and may be extracted, while most of the antimony present in a stable state, they presumably Mineral particles. Thanabalasingam and Picking found that artificially prepared MnOOH, FeOOH, and Al(OH) 3 all adsorbed trivalent europium. The adsorption sequence is manganese > aluminum > iron. Belzile et al. further found that the main effect of artificially prepared hydrated iron and manganese oxides on trivalent europium is: adsorption-oxidation-release, that is, oxidation to pentadose and release. The whole process was determined to be a pseudo first-order reaction with a constant of 0.887±0.167/day (manually formulated hydrated iron oxide), 0.574±0.093/day (naturally hydrated iron oxide), and 1.52 to 2.35/day (manually formulated hydrated manganese oxide). ) [21] . The special adsorption properties between cerium and iron and manganese hydrated oxides can be applied to the treatment of hydrazine. Fourth, the status quo and research progress of cockroach pollution (1) Chemical precipitation method The chemical precipitation method refers to a method of removing the hydrazine in the water by adding an agent, and the usual methods are as follows: 1, adjust the pH According to the principle of solubility product, the low solubility of hydrazine hydroxide in water is removed. Since 锑 is bisexual, how to choose the best pH should be based on the experiment. Zhang Weining et al. used the partial deposition method to remove the ruthenium in the metal alloy solution, first adjust the pH=5~6, filter the solution through the membrane, wash and dry, then adjust the pH=9~10, membrane filtration, washing, drying. By this method, the concentration of rhodium can be reduced from 300 ppm to 25 ppm. 2. Add iron and sulfur ions The mechanism of the removal of bismuth is not the same, and the removal mechanism of strontium by iron salt is still inconclusive. They are classified as one type because both are precipitated by the addition of an agent to remove cesium. Since sulfur ions and antimony are capable of forming insolubles, they are a common method in tailings wastewater treatment. The removal of strontium from iron salts is mainly used in the treatment of drinking water, because iron salt is a common agent in water treatment, which does not cause secondary pollution while removing cockroaches. At the same time, enhanced coagulation is also a more economical approach to water treatment. YuKoNaKamura and TaUashi Tonnnaga use ferric chloride (FC) to have a good flocculation property, and by adjusting the pH, the removal of strontium in polluted water reaches 80% to 90%. Meea K et al. used coagulation beaker experiments with ferric chloride (FC) and polyaluminium chloride (PAC) to treat self-contained and natural water-containing samples. The results showed that the removal of PAC was not significant. FC was a more effective herbicide removal agent. Trivalent europium was easier to remove than pentavalent antimony and was not affected by pH, and the best pH=5 for removing pentavalent antimony was obtained. The author used the polyferric sulfate as a coagulant pilot test to treat the contaminated raw water, and similar conclusions were obtained. 3. pH adjustment combined with iron and salt The treatment is enhanced by adjusting the pH and adding a coagulating agent. Du Jun [ FeSO 4 and Ca(OH) 2 were added together to the tailings wastewater containing hydrazine to cause coagulation and adsorption co-precipitation, and the 3.1 mg/L strontium-containing wastewater was removed to 0.098 mg/L and the main chemical reaction was considered. Yes: (two) electrochemical method The electrochemical reaction of metals is a relatively common phenomenon. Mills T discovered the potential deposition of helium in 1953. Li Hong et al observed the underpotential deposition of trivalent europium on the platinum electrode [26] . This principle is also utilized in the treatment of wastewater. Zhang Zhi [27] used micro-electrolysis-neutralization precipitation method to treat mine wastewater. The process is: let the acidic wastewater pass through a column reactor filled with coke and iron filings, and then neutralize with effluent and alkali. The principle is that when the raw water passes through the reactor, numerous tiny primary batteries are formed; metal ions such as ruthenium are reduced in the cathode (coke) to form a simple substance and remain; the iron of the anode is dissolved in the form of ions, and in the subsequent alkali addition callback It is used as a coagulant with adsorption properties to improve water quality; after treatment, the content of strontium in water can be reduced from 28mg/L to 0.14mg/L. U.S. 1984 Don Heskett the invention high-purity copper zinc alloy called as a KDF filter medium which can be dissolved in water to complete the removal of antimony ions and a portion by electrochemical catalysis, antimony ions dissolved in water was reduced to insoluble The crucible is elemental and plated on the surface and in the middle of the particulate medium. (3) Ion exchange method The most common are ion exchange resins and activated alumina. The mechanism of removal of activated alumina is still unclear. In view of its good adsorption performance for pentavalent antimony and its reference to the principle of defluorination, the author boldly classifies it into this category. Xu Y-H uses commercial activated alumina (AA) as adsorbent and found that it has very good adsorption performance for pentavalent barium ions. The optimum pH is 2.8-4.3, and saturated AA can be regenerated with 50 mM sodium hydroxide solution. The experiment also found that nitrate, chloride and arsenite have little effect on adsorption, while arsenate, EDTA, tartrate and sulfate can significantly reduce their adsorption properties. He also speculated that activated alumina and pentavalent strontium ions are mainly electrostatic adsorption and characteristic adsorption. Studies by Nalan Ozdermir et al. have shown that XAD-8 ion exchange resins have a strong adsorption of inorganic forms of Sb(III) and Sb(V) ions. The optimum pH range of the system is 4-6 (pH). The best effect on Sb(V) is 12.5% ​​lower than the removal of Sb(III). However, the device is used as a pretreatment for analysis and is small in scale. HE years antimony ions exchanged resin was treated with copper electrolyte aminoalkyl phosphoric acid cation chelating groups, but also to achieve better results. (4) Other methods In addition to the above three categories, there are other ways. The Japanese Yamashita uses HCL and a cationic surfactant, and then air is introduced to remove the ruthenium by adsorbing it on the surface of the bubble. Sigworth and Smith reported in 1972 that activated carbon has excellent adsorption properties for hydrazine, but similar reports have not been seen since. V. Outlook The pollution of cesium in the environment is constantly attracting people's attention. With the development and deepening of research, the toxicity and distribution of cockroaches in the environment are constantly being understood. With the establishment of strict environmental standards, it also poses a huge challenge to the water treatment industry. (1) The existence of valence and form in the water environment is very complicated, and its migration, transformation and distribution laws need to be analyzed and discussed in a more systematic and in-depth manner. Due to the lag of detection methods and morphological analysis, it has brought difficulties to relevant theoretical research. (2) The treatment methods in the existing water treatment field are not ideal for the removal of cockroaches, and it is difficult to meet the requirements of water quality standards while taking into account the economics of treatment. On the one hand, the special physicochemical properties of cockroaches motivate people to seek new treatment methods, medicaments and materials; on the other hand, it is necessary to consider increasing the cost of water treatment as much as possible. Therefore, how to find efficient and economically viable means of removal is an urgent problem to be solved. At the same time, the solution of related problems can also provide reference and reference for solving the problem of heavy metal pollution in water pollution.
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