Design And Establishment Of Comprehensive Multipollutants Monitor

Industrialization and urbanization results in increasingly pressures on environment.Controls on the environmental pollution start from the emission monitoring.There are many kinds of environmental monitors,but are limited by their single-phase,single-pollutant and off-line application,which is far more satisfied for the actual demands.The future development of environmental monitoring shows an inevitable trend toward the versatility,synchronization,and real-time performance.This study demonstrated a synchronous comprehensive detection instrument integrating sampling,speciation and detection sub-system,based on automation design,the ultraviolet-visible spectrophotometry,atomic fluorescence spectrophotometry,IR and electrochemical principles.The detection of common and representative pollutants in water bodies and soils include ammonia nitrogen,phosphate,sulfate,and heavy metals such as mercury,arsenic,lead and cadmium,as well as gaseous such as NH₃,SO₃,CO,CO₂,NO and HC.Among of them,the water detection unit is its core sector,and a soil column test unit fulfills the interaction between contaminated soil and contacting water,which was consequently analyzed using the water detection unit.By this means,the pollution level of soils was given by the transformation of pollutants in the soils to the contacting water.Meanwhile,physical parameters such as adsorption and desorption coefficients and permeability coefficient can be obtained.The test results showed well linearity of the standard curve of each pollutant,which was above 0.99 in its R² of the linearity.The detection limits of nitrogen,sulfur and phosphorus related ions reaches 1μg/mL,and the those of four heavy metals reaches 0.1-0.05 ng/mL.The recovery efficiency of mercury in real sample can be over 90%,lead 82%,phosphorus over 76%,and the ammonia nitrogen is 103.2%,The detection errors of CO,CO₂,NO,O₂ and HC are not more than±5%.The soil column experiment correctly showed that the concentration of heavy metals arsenic and cadmium in rinsing liquid decreases with time until the overall died-out,reaching,the equilibrium concentrations of arsenic and cadmium at1.75 ng/mL and 0.013 ng/mL.The construction of this self-made instrument involve one major analysis unit and include many sub-systems such as sampling automation,gas absorption,soil column and data center controlled by LabVIEW-based software and RS232 and RS485 communication protocols to realize the human-computer communication between and the automation of the instrument which greatly reduces the cumbersome manual operation and thus improves the analysis efficiency.In a perspective view,the construction of this instrumental device could be further extended to involve more analysis units,regarding more pollutants and their chemical occurrence.