pDADMAC改性活性炭对水中硝酸盐的吸附特性

相对于生化反硝化,吸附法对NO_(3)^(-)的去除速率更快.自然胶体对NO_(3)^(-)的吸附能力有限,研发高效、低成本、制备流程简便的NO_(3)^(-)吸附剂具有重要价值.用聚二烯丙基二甲基氯化铵(pDADMAC)改性活性炭(GAC),提升其Zeta电位,实现对NO_(3)^(-)的高效吸附,并通过改性前后材料的形貌表征,探究其对水中NO_(3)^(-)的吸附机制.结果表明,pDADMAC负载到了活性炭表面,pDADMAC-GAC表面Zeta电位在pH=4—12范围内都得到了提升,因此在较宽的pH范围内对NO_(3)^(-)都有良好的吸附效果.pDADMAC改性后的活性炭(pDADMAC-GAC)对NO_(3)^(-)的吸附量明显提高,约为改性前的3.36—5.06倍.pDADMAC-GAC对NO_(3)^(-)的吸附动力学过程符合准二级动力学,吸附过程以化学吸附为主;在25℃、pH=6、初始NO_(3)^(-)浓度为15 mg∙L^(-1)条件下,准二级动力学模型计算得到的pDADMAC-GAC对硝酸盐的最大吸附量为3.26 mg∙g^(-1).Langmuir吸附等温线拟合效果最好,表明其主要是单分子层吸附.重复性和干扰性实验表明,pDADMAC-GAC具有可重复利用性,水中共存的SO_(4)^(2−)、H_(2)PO_(4)^(-)和Cl−阴离子对NO_(3)^(-)吸附有一定干扰.综上,pDADMAC-GAC具有作为优良的NO_(3)^(-)阴离子吸附剂的潜力.

改性稻秆阴离子吸附剂的制备及对硝酸根吸附研究

NO_3^-对水环境是污染物,对土壤而言则是肥料,因此NO_3^-高效吸附剂的研发对于水环境治理和土壤保肥均有重要意义。以废弃稻秆为原料,结合物理、化学改性手段制备出稻秆(RS)、生物炭稻秆(RS-B)、乙二胺稻秆(DMF-RS)和乙二胺生物炭稻秆(DMF-RS-B) 4种NO_3^-吸附剂,通过SEM和FTIR等方法表征其表面特性和官能团特性确定改性情况,对比4种吸附剂对NO_3^-的去除效果和有机碳源溶出量。结果表明,4种吸附剂中DMF-RS-B对NO_3^-的去除效果最好。在NO_3^-初始质量浓度为30 mg/L,吸附剂投加量为4g/L,pH=2,吸附时间为10 min时,其最大去除率可达61. 22%,表观吸附量达15. 31 mg/g。吸附剂对NO_3^-的吸附过程符合D-R吸附等温方程(R^2> 0. 99),吸附过程为多分子层吸附且是自发放热过程。通过实际水样测试,DMF-RSB对NO_3^-的吸附效果显著,且出水无二次污染。本吸附剂亦可作为缓释固相碳源及土壤保肥(氮肥)材料,是绿色无污染的吸附剂。

桂花种子膳食纤维理化性质研究

采用化学法制备了桂花种子水不溶性膳食纤维(IDF),产率为82.3%,并测定了桂花种子IDF的持油力、持水力、膨胀力、阳离子交换力及对亚硝酸盐的清除作用。结果表明:当温度为50℃时,桂花种子IDF的持水力和持油力分别达到2.43 g/g和2.46 g/g;其膨胀力为2.1 ml/g,阳离子交换力为0.45 mmol/g。桂花种子IDF还具有吸附亚硝酸盐的作用,在p H=2时对亚硝酸盐的吸附作用最强,为2.98 mol/g。

Clinical value of serum interleukin-18 and nitric oxide activities in patients with prostate cancer

Objective:The aim of the study was to estimate the clinical value of serum interleukin-18(IL-18)and nitric oxide(NO)activities in patients with prostate cancer.Methods:The 50 patients with prostate cancer and 25 control subjects were measured in serum IL-18 by enzyme-linked immunosorbent assay(ELISA)and nitrate+nitrite level by an index of NO generation.Results:Serum IL-18 and nitrate+nitrite levels were significantly higher in patients with prostate cancer when compared to the control subjects(P<0.05).Serum IL-18 level was significantly higher in patients with stages B,C and D when compared to patients with stage A(P<0.05).Serum IL-18 level was significantly higher in the metastatic patients compared with the nonmetastatic patients(P<0.01).There was no difference in serum nitrate and nitrite level between metastatic and nonmetastatic patients(P>0.05).The serum IL-18 and nitrate and nitrite levels decreased after patients underwent surgical resection.Conclusion:Serum IL-18 level may be a useful marker to predict prognosis of patients with prostate cancer after surgery.Long-term follow-up is required to clarify this hypothesis.