This study addresses the synthesis of nanoscale zero-valent iron(n ZVI) in the presence of natural bentonite(B-n ZVI) using green tea extract. The natural bentonite and B-n ZVI were then applied for the removal of pho...This study addresses the synthesis of nanoscale zero-valent iron(n ZVI) in the presence of natural bentonite(B-n ZVI) using green tea extract. The natural bentonite and B-n ZVI were then applied for the removal of phosphorus from aqueous solutions at various concentrations, p H levels and contact time. The desorption of phosphorus(P) from adsorbents was done immediately after sorption at the maximum initial concentration using the successive dilution method. The characterization of FTIR, SEM, and XRD indicated that n ZVI was successfully loaded to the surface of natural bentonite. The sorption of phosphorus on B-n ZVI was observed to be p H-dependent, with maximum phosphorus removal occurring at the p H range of 2 to 5. The results demonstrate that the maximum sorption capacities of natural bentonite and B-n ZVI were 4.61 and 27.63 mg·g^(-1), respectively.Langmuir, Freundlich, and Redlich–Peterson models properly described the sorption isotherm data. For either adsorbent, desorption isotherms did not coincide with their corresponding sorption isotherms, suggesting the occurrence of irreversibility and hysteresis. The average percentages of retained phosphorus released from natural bentonite and B-n ZVI were 80% and 9%, respectively. The results indicated that sorption kinetics was best described by the pseudo-second-order model. The present study suggests that B-n ZVI could be used as a suitable adsorbent for the removal of phosphorus from aqueous solutions.展开更多
文摘目的:研究绿茶水提物对大鼠细胞色素P450(CYP450)酶活力和m RNA表达的影响。方法:SD大鼠随机分组,连续灌胃绿茶水提物或水14 d后,同时给予探针药非那西丁、安非他酮、甲苯磺丁脲和咪达唑仑,采用液相色谱-质谱联用技术(液质联用)测定给药后不同时间点血药浓度,计算药动学参数进而推测CYP1A2、CYP2B1、CYP2C11和CYP3A1酶活力。此外,采用实时荧光定量PCR(real-time PCR,RT-PCR)技术测定CYP450的m RNA表达水平。结果:实验组大鼠安非他酮与甲苯磺丁脲的药动学参数与对照组相比差异有统计学意义(P<0.05),推测绿茶水提物能诱导大鼠CYP2B1酶活力和抑制CYP2C11,而非那西丁与咪达唑仑参数比较差异无统计学意义(P>0.05)。RT-PCR实验发现,绿茶水提物能显著上调大鼠CYP2B1 m RNA水平并下调CYP2C11 m RNA水平,对CYP1A2与CYP3A1没有影响。结论:持续摄取绿茶会改变CYP2B1与CYP2C11酶活力和m RNA表达水平,可能会引起药物相互作用的发生。
文摘This study addresses the synthesis of nanoscale zero-valent iron(n ZVI) in the presence of natural bentonite(B-n ZVI) using green tea extract. The natural bentonite and B-n ZVI were then applied for the removal of phosphorus from aqueous solutions at various concentrations, p H levels and contact time. The desorption of phosphorus(P) from adsorbents was done immediately after sorption at the maximum initial concentration using the successive dilution method. The characterization of FTIR, SEM, and XRD indicated that n ZVI was successfully loaded to the surface of natural bentonite. The sorption of phosphorus on B-n ZVI was observed to be p H-dependent, with maximum phosphorus removal occurring at the p H range of 2 to 5. The results demonstrate that the maximum sorption capacities of natural bentonite and B-n ZVI were 4.61 and 27.63 mg·g^(-1), respectively.Langmuir, Freundlich, and Redlich–Peterson models properly described the sorption isotherm data. For either adsorbent, desorption isotherms did not coincide with their corresponding sorption isotherms, suggesting the occurrence of irreversibility and hysteresis. The average percentages of retained phosphorus released from natural bentonite and B-n ZVI were 80% and 9%, respectively. The results indicated that sorption kinetics was best described by the pseudo-second-order model. The present study suggests that B-n ZVI could be used as a suitable adsorbent for the removal of phosphorus from aqueous solutions.
