Preparation Of Aminothiazole Magnetic Materials And Their Adsorption Properties For Heavy Metals

While the storage and oil and gas shipping,wastewater containing harmful substances such as heavy metals and organic compounds is generated.Heavy metals are biotoxic,difficult to degrade,and can accumulate through the food chain.As environmental awareness grows,the discharge standards for heavy metals in wastewater have become increasingly strict.Therefore,low-cost and efficient treatment of heavy metal-containing wastewater is of great significance for the environmental management concerning the shipping of oil and gas.Adsorption as a means of treating heavy metal-contaminated wastewater that is simple,cost-effective,and has good treatment effects.Aminothiazole is an organic compound with a high density of sulfur and nitrogen groups（heavy metal adsorption groups）.It has high selectivity for heavy metals,especially toxic heavy metals such as mercury and lead.Therefore,this article intends to prepare magnetically responsive adsorbent particles based on aminothiazole using multiple methods and explore their performance in removing mercury from wastewater.The aim is to provide basic data for the removal of heavy metals from oil and gas wastewater.In the first part.Four methods were used to load aminothiazole onto magnetic particles Fe₃O₄@SiO₂,and their ability to adsorb mercury ions was compared.（1）Aminothiazole was oxidized using Cu Cl₂ as an oxidant and loaded onto Fe₃O₄@SiO₂,and the resulting magnetic adsorbent material was labeled as Fe₃O₄@SiO₂@PAT.（2）Polyaminothiazole（PAT）was loaded onto Fe₃O₄@SiO₂ with the assistance of dopamine（DA）,and the resulting magnetic adsorbent material was labeled as Fe₃O₄@SiO₂@DA-PAT.（3）PAT was coupled with Fe₃O₄@SiO₂ microspheres modified by organosilane,and the resulting adsorbent was labeled as Fe₃O₄@SiO₂@SCA-PAT.（4）Fe₃O₄@SiO₂ microspheres modified by organosilane were coupled with aminothiazole（AT）to obtain Fe₃O₄@SiO₂@AT.The results showed that in 100 ml simulated wastewater with a Hg²⁺concentration of 50 mg/L and p H of 1.3,adding 20 mg of adsorbent and adsorbing for 24 h at 25°C,the adsorption capacities of Fe₃O₄@SiO₂@PAT,Fe₃O₄@SiO₂@DA-PAT,Fe₃O₄@SiO₂@SCA-PAT,and Fe₃O₄@SiO₂@AT were 35.7 mg/g,121.9 mg/g,109.1 mg/g,and 43.6 mg/g,respectively（while the adsorption capacity of PAT was 219.8 mg/g）.Obviously,amino-thiazole magnetic adsorbents prepared by loading PAT with dopamine-assisted or silane coupling agent-assisted methods have higher mercury adsorption capacity.In the second part,Fe₃O₄@SiO₂@DA-PAT prepared with dopamine assistance was used to treat mercury-containing wastewater.Under the conditions of p H 5,initial Hg²⁺concentration of 50 mg/L,and temperature of 36°C,the saturated adsorption capacity of Fe₃O₄@SiO₂@DA-PAT for Hg²⁺reached 154 mg/g.Using a 2M mixed acid（hydrochloric acid and nitric acid in a molar ratio of 1:1）as the desorption solution,the desorption rate of Hg²⁺reached 91%.The adsorption kinetics of Fe₃O₄@SiO₂@DA-PAT for Hg²⁺followed a pseudo-second-order adsorption rate equation.In the presence of other metal cations such as Ni²⁺,Mg²⁺,Cu²⁺,Ca²⁺,Zn²⁺,K⁺,Na⁺(at concentrations 20 times higher than Hg²⁺at 400mg/L),the saturated adsorption capacities of Fe₃O₄@SiO₂@DA-PAT for Hg²⁺decreased by17.8%,20.7%,21.2%,26.7%,29.7%,32.1%,and 33.2%,respectively.Fe₃O₄@SiO₂@DA-PAT showed a certain ability to resist interference from other metal ions.In simulated seawater（Na⁺concentration of 10.6 g/L）,the saturated adsorption capacity of Fe₃O₄@SiO₂@DA-PAT for Hg²⁺decreased by 40.9%,indicating that the adsorbent has the potential to treat heavy metal-polluted seawater.In the third part,Fe₃O₄@m-SiO₂@SCA-PAT prepared with coupling agent assistance was used to treat mercury-containing wastewater.Firstly,Fe₃O₄@SiO₂@SCA-PAT was further improved by loading PAT onto 3-chloropropyltrimethoxysilane-assisted mesoporous silica-coated Fe₃O₄@SiO₂,and the resulting adsorbent was named Fe₃O₄@m-SiO₂@SCA-PAT.The Hg²⁺adsorption capacity of Fe₃O₄@m-SiO₂@SCA-PAT was 185 mg/g under the conditions of 50 mg/L Hg²⁺concentration,p H 1.3,and 10 mg adsorbent in 100 ml simulated wastewater at 25°C for 24 h,which was 26%higher than that of Fe₃O₄@SiO₂@SCA-PAT.Secondly,the performance of Fe₃O₄@m-SiO₂@SCA-PAT in treating mercury-containing wastewater was evaluated.The adsorption capacity of Fe₃O₄@m-SiO₂@SCA-PAT for Hg²⁺reached 266 mg/g under the conditions of p H 3.0,initial Hg²⁺concentration of 50 mg/L,and temperature of 30°C.Using a 2M nitric acid as the desorption solution,the desorption rate of Hg²⁺reached 90.4%.The adsorption kinetics of Fe₃O₄@m-SiO₂@SCA-PAT for Hg²⁺followed a pseudo-second-order adsorption rate equation.In the presence of other metal cations such as Ni²⁺,Mg²⁺,Cu²⁺,Ca²⁺,Zn²⁺,K⁺,Na⁺(at concentrations 20 times higher than Hg²⁺at 400 mg/L),the saturated adsorption capacities of Fe₃O₄@m-SiO₂@SCA-PAT for Hg²⁺decreased by 10.1%,16%,15.6%,21.5%,25.1%,28.5%,and 29.9%,respectively.Fe₃O₄@m-SiO₂@SCA-PAT showed a good ability to resist interference from metal cations such as Ni²⁺,Mg²⁺,Cu²⁺.In this study,four kinds of magnetic adsorbent particle materials based on aminothiazoles were prepared and their adsorption capacity of heavy metal Hg²⁺was compared.Then,the adsorption performance,anti-interference performance,desorption performance and characterization analysis of Fe₃O₄@SiO₂@DA-PAT and Fe₃O₄@m-SiO₂@SCA-PAT treatment of mercury-containing wastewater were further explored.The results showed that they have the characteristics of large adsorption capacity,fast adsorption rate,high utilization rate of active components,easy separation and recovery.Finally,the adsorption mechanism was deduced.It provides basic data and further development direction for the treatment of mercury-containing wastewater by aminothiazol-based magnetic adsorption materials.