采用化学发泡法,以普通硅酸盐水泥和粉煤灰为主要原料,制备发泡粉煤灰A级保温材料。系统研究了稳泡剂、促凝剂、纤维以及发泡剂等关键因素对保温材料性能的影响,优化了发泡粉煤灰保温材料配方设计,通过SEM及Image Pro Plus 6.0等手段对试件进行表征和计算,对各因素的影响机理进行了分析。结果表明,当稳泡剂、促凝剂、纤维和发泡剂掺量分别为1.2%,0.050%,0.4%和5.0%时制备的发泡粉煤灰质量吸水率为47.11%、抗压强度为0.523MPa、绝干密度为248.11kg/m3和导热系数为0.067W/(m·K),满足JG/T266-2011《泡沫混凝土》中A03级泡沫混凝土要求。
The effects of solution chemistry conditions and adsorbent surface properties on the adsorption of Ni(II) on Laiyang bentonite were investigated via the batch technique. Potentiometric and mass titration techniques were employed in the batch experimental methods, and the results showed that the point of zero net proton charge(PZNPC) of bentonite at different ionic strength denoted p HPZNPC to be 8.2±0.1. The removal of Ni(II) from the solution increased with an increasing bentonite dosage, with the maximum removal efficiency equating up to 99%. The adsorption of Ni(II) on bentonite increased with an increasing p H value at a p H value of <8.5, and reached a Ni(II) removal efficiency of >99% at a p H value of >10.2. The Ni(II) adsorption performance exhibited different responses to cations(K+, Na+) but was not influenced by the background anions(NO3-, Cl-, and Cl O4-). The adsorption of Ni(II) was dominated by the outer-sphere surface complexation and ion exchange with Na+/H+ on bentonite surface at low p H value, whereas the inner-sphere surface complexation and surface precipitation were the main adsorption mechanisms at high p H value. The adsorption isotherms of Ni(II) on bentonite can be described well by the Langmuir model. The thermodynamic parameters of adsorption, including the Gibbs free energy, the enthalpy change, and the entropy change, at different temperatures indicated that the adsorption of Ni(II) on bentonite was endothermic and spontaneous.
Cao XiaoqiangYan BingqiXue JianliangWang QianWang YapingHuang YongqingZhang YanLyu Xianjun
