MnO_(2)/TiO_(2)改性沸石去除矿井水中Fe^(2+)和Mn^(2+)的试验研究

针对矿井水中Fe^(2+)、Mn^(2+)浓度超标及处理效果不稳定等问题,通过溶胶-凝胶法将纳米MnO_(2)和纳米TiO_(2)负载于天然斜发沸石表面制备出MnO_(2)/TiO_(2)改性沸石滤料,并分析了沸石改性前后的微观形貌和孔隙结构.采用单因素动态吸附试验和Thomas模型拟合探究了MnO_(2)/TiO_(2)改性沸石对模拟矿井水水样中Fe^(2+)、Mn^(2+)的去除效果及机理,并考察水流速度、滤层厚度、溶液pH及硬度对去除效果的影响.结果表明:较天然沸石而言,MnO_(2)/TiO_(2)改性沸石的比表面积、孔径、孔体积和阳离子交换量明显增大.当水流速度为7 m/h、进水pH为9.5、水质硬度为350 mg/L、滤层厚度为110 cm时,改性沸石对Fe^(2+)、Mn^(2+)的最大吸附量分别为44.810、6.549 mg/g,且Thomas模型能较好地拟合改性沸石对Fe^(2+)、Mn^(2+)的吸附动力学特征.反冲洗试验结果表明,反冲洗强度为13 L/(m^(2)·s),反冲洗时间大于7 min时,改性沸石的再生效果良好,可重复使用.研究显示,本文制备的MnO_(2)/TiO_(2)改性沸石吸附滤料可为同步去除矿井水中Fe^(2+)、Mn^(2+)污染提供一种解决办法.

硝酸改性煤基活性炭吸附处理垃圾渗滤液

采用硝酸对煤基粉末活性炭进行改性处理,考察不同改性条件下活性炭吸附性能的变化,并将最优改性条件下所得的活性炭用于对垃圾渗滤液的深度处理,考察活性炭的不同投加量和吸附时间等参数对污染物的去除效果。试验结果表明:在硝酸浓度15%、改性温度60℃、改性2 h后,改性活性炭中孔孔径的比例最大,吸附性能最佳;在改性活性炭处理垃圾渗滤液试验中,当活性炭投加量为4 g/150 mL、吸附时间为12 h、溶液pH值为7时,化学需氧量(COD)、氨氮(NH3-N)、总氮(TN)、六价铬(Cr6+)的去除率分别为79.0%、43.3%、52.6%和100%。改性后,活性炭对COD和TN的去除率较改性前分别提高10.1%和17.3%。对COD吸附降解动力学分析发现,改性活性炭12 h内吸附降解COD的反应更符合零级动力学反应。对降解过程进行非线性拟合表明,降解过程可由Logistic函数模型模拟和预测。利用超声波法,在pH值为4.5的酸性条件下超声2 h以上时,对改性活性炭再生后恢复效果较好,以UV254为参考值,再生后处理率相比初次使用时仅降低12%,可重复利用。

Analysis of Abnormal Characteristics of Regional Crustal Deformation before the Menyuan MS6.4 Earthquake by GPS Continuous Data

In order to study the characteristics of crustal deformation around the epicenter before the 2016 M_S6. 4 Menyuan earthquake,the GPS continuous stations of the period from 2010 to 2016 were selected according to the observation data of the tectonic environment monitoring network in Chinese Mainland. The deformation characteristics of the crust before the earthquake were discussed through inter-station baseline time series analysis and the strain time series analysis in the epicentral region. The results show that a trend turn of the baseline movement state around the epicenter region occurred after 2014,and the movement after 2014 reflects an obvious decreasing trend of compressional deformation.During this period,the stress field energy was in a certain accumulation state. Since the beginning of 2014,the EW-component linear strain and surface strain rate weakened gradually before the earthquake. It shows that there was an obvious deformation deficit at the epicentral area in the past two years,which indicates that the region accumulated a high degree of strain energy before the earthquake. Therefore,there was a significant background change in the area before the earthquake. The results of the study can provide basic research data for understanding the seismogenic process and mechanism of this earthquake.