RESUMO
ABSTRACTThe problem of wastewater pollution in the production of monosodium glutamate (MSG) is becoming more and more serious. A novel type of chemically modified Salix psammophila powder charcoal (SPPCAM) was synthesized to address the chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) in MSG wastewater. SPPCAM was prepared by carbonization method, in which inorganic ammonium molybdate (AM) was used as modifier and Salix psammophila powder (SPP) was used as raw material. Under optimal treatment conditions, maximum removal rates (removal capacities) of 45.9% (3313.2â mg·L-1) for COD and 29.4% (23.2â mg·L-1) for NH3-N in MSG wastewater were achieved. The treatment results significantly outperforming the unmodified Salix psammophila powder charcoal (SPPC), which only achieved removal rates (removal capacities) of 10.6% (763.9â mg·L-1) for COD and 12.9% (10â mg·L-1) for NH3-N. SPPC and SPPCAM before and after preparation were analysed by FT-IR and XRD, and Mo ions in the form of Mo2C within SPPCAM were successfully loaded. SEM, EDS-Mapping, BET, and other methods were used to analyse SPPCAM before and after MSG wastewater treatment, demonstrating that SPPCAM effectively treated organic pollutants in monosodium glutamate wastewater. The NH3-N in the treated MSG wastewater has reached the standard of safe discharge.
RESUMO
OBJECTIVE: To study a glucan (GB II) isolated from Gastrodia elata. METHODS: The glucan was obtained with water extraction, alcohol precipitate, DEAE-Sepharose Fast Flow column and Sepharose CL-6B column chromatography; sugar composition analysis, IR and NMR were used to determine the structural feature. RESULTS: The molecular weight of the glucan was 4 300 dalton estimated by HPGPC; it contained 27 glucose residues, which mainly composed of alpha-D-(1-->4)-glucose with little glucuronic acid and branch O-6 points. CONCLUSION: The glucan was a new glucan for the first report from Gastrodia elata.