Preparation Of Photocatalyst Loaded Activated Carbon Grafted With Polyhydrazide For Removing Formaldehyde

As a common chemical material,urea-formaldehyde resin adhesives are widely used in after-finishing hardeners,wood stitching agents and decorative coatings,etc.,but,There is generally a problem with excess limit of free formaldehyde in such adhesive products due to the lack of Urea-free hydroformylation process in the preparation.Not only that,urea-formaldehyde resin adhesives are also decomposed and slowly release formaldehyde because the influence of shift from environmental temperature and humidity,which poses a great latent hazard to the human health of the living environment.the lower concentration of formaldehyde can cause discomfort,such as corneal swelling,asthma,cough,chest tightness,etc,living in high concentrations of formaldehyde for a long time may cause A549 cell lesions and induce cancer and genetic mutations.The formaldehyde pollution in the textile field mainly results from printing and dyeing auxiliaries and various resin binders such as urea-formaldehyde resin,phenolic resin,bis-naphthol S-formaldehyde and dicyandiamide formaldehyde resin.It was tried for the formaldehyde caused by chemical decomposition that various methods of removing formaldehyde such as photocatalytic oxidation,activated carbon adsorption,chemical reaction and biological decomposition.However,every method in the above has its large engineering application defects and cannot achieve safely and efficiently removing formaldehyde.For example,activated carbon adsorption and chemical absorption have secondary pollution problems,and photocatalytic oxidation technology can be effective when the catalysts were placed in ultraviolet environment.Therefore,there has been an urgent need to develop new formaldehyde-removing materials which has highly efficiency and has no secondary pollution.In this paper,the polyacrylamide?PAH? formaldehyde removal material was prepared by both of free radical and transesterification reactions according to the characteristics of polyamine materials,such as excellent adjustability of molecule structure,sensitive capture capability for formaldehyde,large capacity for formaldehyde and high affinity for polyamide fibers.Then,the visible light photocatalyst?Mnx/Agy-TiO₂? which responds in the visible spectrum had been successfully prepared by one technology that various metal elements changing the lattice of titanium dioxide was doped in its sol.the polyacrylamide grafted activated carbon material?ACm-g-PAH? and visible light photocatalyst loaded polyhydrazide grafted activated carbon material?Mnx/Agy-TiO₂-l-ACm-g-PAH? had been carried out by using load and chemical grafting technology.Those technologies could not only enhance its adsorption capacity of formaldehyde,but also completely solve the problem of secondary pollution of formaldehyde.Finally,it were prepared of the functional textiles with removing formaldehyde by transfer printing technology with Mnx/Agy-TiO₂,ACm-g-PAH and Mnx/Agy-TiO₂-l-ACm-g-PAH as color paste additives.The maximum formaldehyde removal rate of Mnx/Agy-TiO₂-l-ACm-g-PAH is more than 99.8%.So that curtains,murals,carpets and other families decorations have become formaldehyde removal tools.When the initial formaldehyde concentration in the room exceeds 10 times?0.8mg/m³?,the room area is 15square meters?the house height is 3.16m?,and the formaldehyde in the room for one year?365 days? is removed to a safe level?below 0.08mg/m³? requiring 955g of ACVPRF Textile?curtain or carpet?.The specific research work of this paper is summarized as follows:?1?The polyhydrazide materials were prepared by free radical and transesterification reactions.The effects of initiator and synthesis temperature on the polymerization degree of polymethyl acrylate were studied.The reaction characteristics of polymethyl acrylate with different polymerization degrees and hydrazine hydrate was investigated.The key factors affecting formaldehyde removal rate,mechanism of the reaction of polyhydrazide and formaldehyde and regeneration rule of polyhydrazide-formaldehyde were analyzed.The results show that the better initiator of polymethyl acrylate is azobisisobutyronitrile.The preferred preparation process of polyhydrazide is transesterification temperature of 70?,ester group_?PMA?:amine group_?HH??in molar ratio? of 1:1.3 and reaction time of 8 hours,and the yield was 86.3%.The regeneration formula was Na₂HPO₄,NaH₂PO₄ and MnO₂.?2?Nano-visible light photocatalyst was prepared using tetrabutyl titanate(C₁₆H₃₆O₄Ti) as precursor by sol-gel method.The effects of nano-titanium dioxide doped different metal elements?La,Ce,Ag and Mn?on the response spectrum of the catalyst were compared.The crystal parameters and main components of nano-TiO₂ doped MnO₂ and AgNO₃ were analyzed by XRD.The effects of activation temperature,activation time and doping element on formaldehyde removing rate and the kinetic data of the catalyst catalyzing formaldehyde were investigated.The results show that the Mnx/Agy-TiO₂ powder with the activation temperature of 550?,activation time of 2h and MnO₂:AgNO₃:C₁₆H₃₆O₄Ti?by mass ratio? of3:2:1000 has the best visible light photocatalytic activity and its main component is Ag₂Mn₃TixO₄ and AgMnTixO₄.The kinetic data of photocatalytic formaldehyde is better fitting the zero-order reaction kinetics model at a formaldehyde concentration of less than5.3?g/mL,while the kinetic data of catalytic formaldehyde by Mnx/Agy-TiO₂ is well fitted to the first-order reaction kinetics model at a formaldehyde concentration of more than15.8?g/mL.?3?ACm-g-PAH was prepared by grafting polyhydrazide onto activated carbon modified by nitric acid using condensation reaction.To eliminate the possibly secondary pollution,Mnx/Agy-TiO₂ was directly supported on the surface of ACm-g-PAH,and the self-purifying removal formaldehyde material?Mnx/Agy-TiO₂-l-ACm-g-PAH? was further assembled.The effects of the pore structure from the above two materials on formaldehyde capacity and formaldehyde removal mechanism were analyzed.The effects of the preparation process on their formaldehyde removal rate were studied.The effects of relative humidity,temperature and washing times on their application properties were also discussed.The results show that formaldehyde removal rate of ACm-g-PAH was highest when the activation temperature of90?,the condensing agent DCC of 2.5% and the PAH molar concentration of 12 mmol/L,the formaldehyde removal rate is 99.6%.when the preparation conditions were the activation temperature of 650?,the activation time of 120 min,the PAH grafting solution concentration of 11 mmol/L,the shrinkage agent DCC?mass percent? of 2% and the ACm:Mnx/Agy-TiO₂of 20:1,the formaldehyde removal rate of 0.5g Mnx/Agy-TiO₂-l-ACm-g-PAH material in50mL formaldehyde solution of different concentrations?3.2?g/mL-25?g/mL? all exceeded99.5%.The temperature and humidity have little effect on the formaldehyde performance of Mnx/Agy-TiO₂-l-ACm-g-PAH.?4?The formaldehyde-removing functional textiles suitable for different formaldehyde concentrations were developed using the grafting and coating printing technology.Firstly,the cross-linking agent LCX was synthesized,the removal formaldehyde fiber of PA6-g-LCX-PAH was prepared by ketoamine reaction.The effect of crosslinker LCX on the formaldehyde removal rate and formaldehyde removal mechanism of PA6-g-LCX-PAH was studied.The effect of PA6-g-LCX-PAH on the optimum application process and formaldehyde removal mechanism was studied.The results show that the optimal preparation process of PA6-g-LCX-PAH is pH of 6,activation temperature of 100?,PAH concentration of 30 g/L and the initiator AIBN concentration of 1.5%?by mass fraction?.The glass transition temperature of PA6-g-LCX-PAH is from 36.8? to 58.1?.The optimum preparation process for ACVPRF Textile is DF of 20%,XRF of 3%,indigo pigment of 2%?o.w.f? and Mnx/Agy-TiO₂-l-ACm-g-PAH of 1.8%?o.w.f?,and 1 g ACVPRF Textile had a formaldehyde removal capability of 4.58 mg.