Dynamic Study On Aggregation And Transformation Of Silver Nanoparticle Under The Combined Action Of Various Factors

Silver nanoparticles(AgNPs),as one of the most widely used metal nanomaterials,can enter the water and soil environment through various channels to produce toxicity to aquatic organisms,which can damage the ecological environment of water.Understanding the transformation of nanosilver under the combined action of multiple factors can be used for reference for studying the biological toxicity of nanosilver under the actual conditions.The toxicity of nanosilver in the environment mainly depends on two aspects:(1)Nano-silver particles themselves are toxic;(2)biological toxicity caused by silver ion dissolution caused by the conversion of nano-silver.The main factors affecting the transformation of nanosilver in the environment are: pH,ionic strength,temperature,Cys concentration,AgNP concentration,ion type and so on.These factors will affect the transformation of silver nanoparticles and biological toxicity.This article intends to study the above factors affecting the mechanism of silver nanosilver transformation,and based on statistical analysis and numerical methods to quantify the interaction between the various factors to establish the leading factor affecting the stability of nanosilver.The experimental data obtained the following conclusions:(1)silver nanoparticle surface PVP can replaced by Cys,silver nanoparticle particle size reduced by 20-30 nm.For the Cys replacement process found that different types of ions change a single factor pH,Cys concentration,AgNP concentration,temperature,the replacement rate of change trends are also different;When two or more kinds of factors work together,most of the influencing factors are mutually antagonistic,and a small part is synergistic,which is related to the type of particle.(2)The statistical analysis shows that the main influencing factors of sodium nitrate and calcium chloride solution are ion intensity and negative effect,The main influencing factors in sodium chloride are ionic strength,interaction of Cys concentration and temperature,interaction of pH and ionic strength,and ionic(3)strength,The interaction between Cys concentration and temperature is a negative effect,The interaction between pH and ionic strength is a negative effect.(4)When the nano-silver instability occurs coagulation,nano-silver particle size increased to 2-10 times within 3h,by analyzing the nano-silver polymerization process shows that the ionic strength is the main reason for nano-silver condensation,The effect of different salt solutions on the other five factors(pH,ionic strength,temperature,Cys concentration,silver nanoparticle concentration)at high ionic strength was different.(5)The statistical analysis shows that the significant positive effect on the nano-silver coagulation in sodium nitrate is ionic strength,temperature,ionic strength and temperature.The significant negative effects are nano-silver concentration,nano-silver concentration and ionic strength,Cys concentration and temperature.The significant positive effect that affects the silver nanoparticles in the sodium chloride solution is the ionic strength,and the significant negative effects are the nano-silver concentration,the nano-silver concentration and the ionic strength.The significant positive effect that affects the silver nanoparticles in the calcium chloride solution is the ionic strength,and the significant negative effects are the nano-silver concentration and the nano-silver concentration * ionic strength.(6)The experimental results show that the main factors of Cys displacement and nano-silver coagulation are ionic strength,showing negative effect in displacement,reducing displacement,showing positive effect in coagulation,and promoting coagulation.The results imply that in natural groundwater environment,if the ion concentration is large,the nano-silver is not stable to coagulation and the toxicity is reduced.If the concentration of the nano-silver is too large,the greater and more stable the nano-silver concentration is,the higher the toxicity is The bigger These findings have reference value for understanding the ecological toxicity of nano-silver in contaminated sites.