New Efficient Tobacco-Specific Nitrosamines Trap Derived From Discard Cigarette Butt

In response to the increasingly severe ecological environment and human health issues,this thesis aimed to design and develop environmentally friendly adsorbent with high efficiency to selectively capture tobacco-specific nitrosamines(TSNA),with the new strategy of converting waste into the high-efficiency,low-cost,multi-functional and sustainable sorbents to eliminate environmental carcinogens and heavy metal ion pollution.At the same time,we explored the liquid phase adsorption mechanism of TSNA by porous materials to broaden the design ideas of shape-selective adsorbents.In addition,we also attempted to design new menthol carrier to meet the thermal release of menthol in new tobacco products,with the aim of reducing the harm of tobacco.The thesis consists of four parts:1.We used discarded cigarette butt(DCB)as carbon source,aluminum nitrate as pore-forming agent,along with the one-pot method without template and no washing to synthesize the high-efficiency carbonaceous adsorbent.New sorbent with a developed porosity and the well-exposed metal oxides could selectively adsorb TSNA in solution,capturing 25%of TSNA among hundreds of components in tobacco extract solution or 35 mg g^-1of 4-methylnitrosamino-1-3-pyridyl-1-butanone(NNK)in aqueous solution,quite better than activated carbon and zeolite Na ZSM-5.In addition,the sorbent could catalyze the degradation of the adsorbed NNK in 472-584 K to eliminate the environment carcinogen at relative low temperature.The cell viability test proved the safety of this DCB-start adsorbent for the first time.The characteristics of low cost,facile preparation,excellent performance and easy regeneration made the new adsorbent own good prospects of application.2.New selective carbonaceous sorbent was one-pot fabricated using microburst of bi-metal salts in order to eliminate carcinogens in environment.We used DCB as carbon source,aluminum nitrate and ferrous acetate as pore-forming agents to prepare the versatile sorbent with a developed porosity and the well-exposed metal oxides in order to replace zeolites for the selective adsorption in environment protection.Numerous finely divided porous particles endowed the composite specific surface area of over 350m²g^-1,enabling it to be the best sorbent of TSNA to date in solution.It adsorbed 41%of TSNA among hundreds of components in tobacco extract solution or 142 mg g^-1of NNK in aqueous solution,and rapidly trapped Pb(?)ion at the S/L of 0.2 within 10min with a capacity of 153 mg g^-1.Moreover,new sorbent could catalyze the degradation of NNK in mild conditions,which is rare but very important for environmental protection.3.A new way of controllable releasing menthol with amorphous silica was reported firstly.Porous silica adsorbed menthol in 373-413 K and then was covered with cellulose acetate film to form a carrier-embedded menthol.The sealed menthol would be released at elevated temperatures once the cover fractured.Here the influence of temperature and nature of sorbent on the adsorption of menthol,and the thermal release of menthol was studied with headspace gas chromatography method.Silica adsorbed about 400 mg g^-1of menthol at the optimal adsorption conditions,and released most of them at about 473 K.Preliminary application in non-combustible cigarette proved the feasibility of thermal release of menthol with the covered silica carrier.4.In the preliminary study on the adsorption of TSNA by ZIF-8,we explored the adsorption capacity of ZIF-8 in the NNK and NNN aqueous solutions.Using NNK,NNN and NPYR to study the adsorption kinetics of ZIF-8,it was found that the adsorption of TSNA by ZIF-8 is probably mainly based on the?-?stacking effect and hydrophobicity between the imidazole ring of ZIF-8 and the pyridine ring of TSNA.