To increase the adsorption capacity of the Corylus heterophylla Fisch(HS) for Pb 2+ , HS was chemically modified using NaOH aqueous solution and 95% ethanol and was labeled as SHS; then SHS was chemically modified using mercaptoacetic acid. The SHS modified with mercaptoacetic acid(MHS) was characterized using FTIR, SEM, and XPS. The results indicated that the —SH group was present on MHS, and after Pb 2+ adsorption, the absorption value of the characteristic peak of the —SH group decreased. The adsorption and desorption properties of this functionalized material were investigated as well as the influences of parameters, such as pH value, type of desorption reagent, dosage, flow rate and maximum sample volume. The Pb 2+ adsorption of MHS reached a maximum with pH>5. The experimental data of Pb 2+ adsorption using MHS were fitted using the Langmuir isothermal adsorption model, and a maximum adsorption capacity of 61.54 mg/g was obtained. This was much higher than the adsorption capacity of SHS before modification with the thiol group. After adsorption, MHS was desorbed using a 0.2 mol/L HCl solution, and the percent of desorption was higher than 99%. MHS was used as a solid-phase extractant in the analysis and determination of Pb 2+ content in food and water samples, and the enrichment times achieved 150-fold.
Xiong Yang,Qian Zhang,Ning Yang,Muxi Chang,Yaoyao Ge,Huirong Zhou,Guolei Li
Quercus variabilis and Quercus aliena are two native tree species in China, which have similar habitats, and their regeneration mainly depends on acorn dispersal. This study analyzed the contents of water, soluble sugar, starch, soluble protein , and total phenolics in acorns and cupules during the whole development process to explore the difference between species. Thereinto, starch and total phenol occupied the dominant roles as their high contents. The acorn starch contents increased sharply during development in both species, but the contents in Q . variabilis were almost twice those of Q . aliena when mature. Similarly, high expression levels of starch synthase , soluble starch synthase 2 ( SSS2 ) were also found in the acorns of Q . variabilis . The total phenol contents in Q . variabilis acorns were high at the early stages, and decreased sharply to similar contents in Q . aliena when mature. Additionally, the cupules in Q . variabilis had high contents of total phenols during the whole development period. Similar trends were also found in the expression patterns of UGT84A13 and SDH . The high total phenols in acorns and cupules of Q . variabilis probably protect the acorns from Mechoris ursulus , as only Q . aliena suffered a severe pest infestation in the early development stages. This study not only clarifies the interspecific difference between storage and defense substances during the development process in acorns and cupules, but also deepens understanding the specialized mechanisms of plant–pest/animal interactions in Quercus .
危险品化学品经营许可证（带存储）