The influences of dosage of oxidation substances and intercalation substances,the oxidation time and temperature,the intercalation time and temperature on the swelling volume of sulfur-free expanded graphite were investigated.The optimal conditions for preparing sulfur-free expanded graphite are as follows: the rate of graphite(g),concentrated nitric acid(mL),30% H2O2(mL) and acetic anhydride(mL) is 1∶2.25∶0.25∶0.6;oxidated at 30℃ for 60 min,intercalated at 60℃ for 90 min.Under these conditions,the sulfur-free expandable graphite swelling volume reached 317 mL/g.The expanded graphite was characterized by FT-IR spectroscopy,X-ray photoelectron spectroscopy,X-ray diffraction and scanning electron microscope.The expanded graphite adsorption capacity for crude oil and diesel reached 66.3 g/g and 62.7 g/g,respectively.Its first regeneration efficiency after adsorption of crude was 49.1%,while the crude reuse efficiency was 64.5%.
通过正交实验确定了化学氧化法制备膨胀石墨吸附剂的最优条件,即每10 g鳞片石墨与20 mL98%的浓H2SO4、1 mL 30%的H2O2,于30℃下恒温反应,水洗干燥后在1 000℃下高温膨化。采用BET法和SEM对该吸附剂进行了表征,并对其吸油性能和再生性能进行了研究。结果表明,将该吸附剂用于纯油吸附,其对食用调和油的吸附量可达78.1 g/g,且第1次再生效率为58.2%。
To solve the environment pollution caused by accumulation of discarded waste chelating resin,a method for resin resource was designed with reference of the synthetic route of resin. Under a certain concentrations of diethylamine,waste chelating resin was modified into a AN-DVB containing amidoxime group by adding hydroxylamine,resulting from that nitrile group was transformed into amidoxime group. Experimental conditions were discussed. Effects of reaction time,reaction temperature,concentration of diethylamine,HCl·NH2OH concentration and NaOH concentration on the ratio of transformed into amidoxime group were investigated,the recycling use of resin and diethylamine were studied. Results showed that the maximum adsorption of chelating resin can achieve 90% for the adsorption of metal ion Cu (II) when concentration of diethylamine was 70% ,NaOH concentration was 2mol/L,HCl·NH2OH concentration was 1.2mol/L,reaction temperature was 50℃,and reaction time was 2h. After recycling use of the resin for 4 times,the adsorption of chelating resin was still more than 60%. The chelating resin was characterized by Fourier transform infrared spectroscopy (FT-IR). In the process of reaction,the diethylamine was used as activator.
