Preparation Of Pulp Fibre-based Detection Of Ag(?) Materials And Its Identification Mechanism

In this paper,from the perspective of high-value utilization of biomass materials,the biomass pulp fibre-based visible detection of Ag(?)materials was controlled to prepared by grafting recognize group onto the surface of pulp fibre(PF)via the structural design.The as-prepared materials showed excellent selectivity towards Ag(?),and a mechanism for the selective identification of Ag(?)was proposed.1.The pulp fibre(PF)as raw material,2,5-dithiodiurea(DTu)as a functional reagent,CS/C=S and-NH2/-NH-were anchored to the fibre by a variant thiolation reaction.A pulp fibre-based Ag(?)/Cu(?)detecting material(PF-DTu)was prepared.In mixed metal ion solution,PF-DTu preferentially recognizes Ag+,and PF-DTu exhibits colour response(white to yellow)at 10 s,and its detection limit(10-7 mol/L)is lower than the highest content of drinking water Ag+(0.05 ppm)in the National Drinking Water Hygiene Standard"GB5749-2006";Without Ag+ in the solution,PF-DTu selectively recognizes Cu2+,and the PF-DTu colour becomes dark at 10 s,and its detection limit(10-7 mol/L)is lower than the highest content of drinking water Cu2+ specified by the World Health Organization(2 ppm)standard;PF-DTu is appropriate for a wide range of pH(2?6).It is shown that PF-DTu can rapidly on-site detect Ag+ and Cu2+ in real water sample.The chelate recognition group is chemically bonded to the pulp fiber by chemical anchor,which overcomes the trouble that the heavy metal ion detection function reagent is easy to fall off when the function reagent is physically loaded on the substrate,and result in the detection performance is unstable.2.The pulp fiber as raw material,the active site(H-C=O)is generated in situ on the surface,and L-lysine of the two-coordinate structure is carried out to prepare pulp fiber-based detect of Ag(?)materials(DAPF-L-lys)by Schiff base reaction.In mixed metal ion solution(Ag+,Cu2+,Pb2+,Mn2+,Mg2+,Zn2+,Hg2+),DAPF-L-lys,and the colour of DAPF-L-lys gradually turned brown at 10 s,and its naked-detection-limit could reach 10-7mol/L;In mixed metal ion solutions(Ag+,Cu2+,Pb2+,Mn2+,Mg2+,Zn2+,Hg2+),DAPF-L-lys shows excellent selectivity towards Ag+ and produces a rapidly(10 s)colour response(light yellow to dark brown).The naked-detection-limit can reach 10-7 mol/L,and it can be used for on-site rapidly detection of Ag+ in real water sample.The mechanism illustrated that pulp fiber and the two-coordinate structure(-NH2/-COOH)of L-lysine synergistically realized the enrichment and visual detection of Ag+(ppb level).