Preparation And Herbicidal Activity Of Glufosinate-ammonium Nano-preparation Based On Biochar And Hollow Mesoporous Silica

Nanotechnology can reduce the loss of pesticides before reaching the target,improve the utilization rate,and reduce the pollution to the environment.Nano preparation based on nano-biochar and hollow mesoporous silica were prepared for glufosinate-ammonium,an organophosphorus herbicide with positive temperature effect,and evaluated the activity of glufosinate-ammonium nano-formulations on Erigeron canadensis L.and Echinochloa crus-galli L.in this paper.The main research results are as follows:(1)Using wheat biochar as raw material,nano biochar(NBC)was obtained by wet ground with sand mill.After loading glufosinate(Glu)by physical adsorption,the self-polymerization of dopamine(DA)under alkaline conditions was used to encapsulate NBC to obtain glufosinate-ammonium nano-preparation(Glu@NBC@PDA).The nano-preparation was characterized by Transmission electron microscopy(TEM),Scanning electron microscopy(SEM),Brunauer-Emmett-Teller(BET),Fourier transform Infrared light(FTIR)and Thermogravimetric and Differential thermal analysis(TGA-DTG).Glu@NBC@PDA was successfully prepared with good dispersibility and the loading rate of glufosinate was 12.4%.The photothermal conversion test results indicated that the prepared carrier had high photothermal conversion performance and could convert near-infrared light in sunlight into heat energy.The release rate of glufosinate-ammonium nano-preparation was faster at 40℃ than at room temperature.Moreover,the carrier had good adhesion on E.crus-galli leaves and could resist rainwater scouring.The results of the herbicidal activity test demonstrated that the efficacy of Glu@NBC@PDA on E.canadensis was significantly higher than that of the 18%glufosinate aqueous solution 7 days after treatment with the same dose.(2)Hollow mesoporous silica(HMS)with 130 nm diameter was synthesized by the hard template method as a carrier.After loading glufosinate-ammonium by physical adsorption method,polydopamine(PDA)was encapsulated on the surface of drug-loaded HMS to obtain glufosinate nano-preparation(Glu@HMS@PDA).The nano-preparation was characterized by energy dispersive analysis(EDS),TEM,SEM,BET,FTIR and TGA-DTG,etc.The results showed that the Glu@HMS@PDA was successfully prepared with good dispersion,and uniform particle size and the drug loading rate was 17.4%.Glufosinate-ammonium nano-preparation completely released glufosinate-ammonium within 24 h and its release rate was further accelerated at 40℃ compared with room temperature.Photothermal performance test results showed that Glu@HMS@PDA had quite good photothermal conversion performance.The adhesion test results showed that the nanocarrier HMS@PDA had higher leaf adhesion and anti-rain erosion ability than HMS.The results of the herbicidal activity test showed that the efficacy of Glu@HMS@PDA on E.canadensis was significantly higher than that of the 18%glufosinate aqueous solution 7 days after treatment with the same dose.