The Material Balance Of Fluoride And Chloride In Photovoltaic Enterprises And Their Residue In The Surrounding Environmental Media

A vast amount of contaminants of fluoride and chloride are discharged fromphotovoltaic industry originated from the production of polycrystalline silicon to theassembly of solar cell, which could produce, however, for the reason that the existingtechnology yet cannot be effectively recycling them that the pollutants via effluent,exhaust gas and solid trash to be distributed into different environment media, such asatmosphere, water, soil and plant, furthermore, the chloride and fluoride access to soil,water, and organisms similar to heavy metal which are not degradable and couldeasily be accumulated in the environmental media, so they cause pollution with thecharacteristics of concealment, hystereticnature, irreversibility and long term.Therefore, to analyze the residual fluoride and chloride in different environmentalmedia around photovoltaic enterprises, and study the residual characteristics, variationrules and pollution sources of fluoride and chloride in every phase would providetheoretical basis for ecotoxicological diagnosis and ecological restoration of pollutioncaused by fluoride and chloride compounds from photovoltaic enterprise, which isuseful for environmental protection and sustainable development of the photovoltaicindustry.The study surveyed the source and usage amount of fluoride and chloride inphotovoltaic enterprise and combined with the technology material balance was done.Besides, the study took the measure of integrate point and sphere investigation toarrange the experimental points reasonably, where five water samples, ten soilsamples and six plant samples were collected surrounding photovoltaic enterprise,after that chromatography was used to assay the residual concentrations of fluorideand chloride in them.The results showed that all water samples contained fluoride and chloride with thehighest residual concentration was10.2mg/L and13866.9mg/L respectively. Inaddition, the highest concentration of fluorine ions was the number three drainageoutlet of Yuan Water sand bank, however, the highest concentration of chloride wasthe number three drainage outlet of Yuan Hui canal. Nevertheless, Yuan river had the least amounts of fluoride and chloride. So both contaminants had very high residualsin Yuan Water and Yuan Hui canal, which might be ascribed to the effluentcontaining high levels of fluorine and chlorine elements discharged by photovoltaicindustries. Yuan River is main water resource for the residents, so water qualities areeffectively controlled and processed by government, and it contains low contents offluorine and chloride ions, so which accord with the requirements of the standardsrefer to the environmental quality of surface water, that are GB3838-2002, Ⅲ.The highest fluorine concentrations were found on the fourth layer of soil that was15to20centimeters below soil surface, which indicated that the surface fluoridecould be injected into soil, so the fluorine content had the trend of gradually migrationfrom surface to deep soil. The highest chlorine concentration was found on the secondlayer of soil that is from5to10centimeters, which indicated that chloride is highlymobile but less active than fluoride, so that chlorine can be accumulated in upperlayer soil. There were twenty percent of the soil samples contained fluorine ions withthe concentrations ranging form5.7to11.4mg/kg, which belonged to mild pollution.Also ninety percent of the soil samples contained chlorine ions with the concentrationabove l0mg/kg, belonging to high pollution.As for plants, they had obviously different functions to absorb fluoride, theefficiency from strong to low were Atriplex hortensis, Setaria viridis, Kyllingabrevifolia, Adiantum capillus-veneris, Antenoron filiforme and Flos chrysanthemi, inwhich the Atriplex hortensis had fluorine content of422.7mg/kg, the Floschrysanthemi was6.0mg/kg. Nevertheless, there were only leaves had residuefluorine in the samples, whose sources were exhaust gases containing fluorine ions.The general trend of chlorine content in plants from high to low were stem, leaf androot, so that it was indicated that stem had a rather high efficiency to absorb andaccumulate fluorine ions.