【摘 要】
:
Heavy metals-polluted water has negative impact on the ecosystem. In Malaysia, minimum discharge limit for Cu2+ and Zn2+ are 1 mg/L and 2 mg/L, respectively. Zeolite is a highly porous adsorbent and its performance is affected by various factors, includin
【机 构】
:
Centre for Water Research,Faculty of Engineering,Built Environment and Information Technology,SEGi U
论文部分内容阅读
Heavy metals-polluted water has negative impact on the ecosystem. In Malaysia, minimum discharge limit for Cu2+ and Zn2+ are 1 mg/L and 2 mg/L, respectively. Zeolite is a highly porous adsorbent and its performance is affected by various factors, including contact time and pH. Thus, the objective of this study is to identify an ideal operating condition to treat Cu2+ and Zn2+ solutions up to the allowable discharge limit, by considering the pH and contact time factors. Six kinetic models were studied to identify the adsorption mechanism of the heavy metal removal process. Single solute batch adsorption experiment was conducted within pH 3-11 from 30 to 150 min. Results showed that hydration enthalpy (ΔHhyd ) governed the selectivity of heavy metals, where a maximum of 90. 87% Zn2+(ΔHhyd = -1955 kJ/mol ) and 82. 15% Cu2+(ΔHhyd = -2010 kJ/mol) removals were found at pH≥7. Without pH adjustment, selectivity towards Cu2+ was higher compared with Zn2+ due to the size of hydration radii, where Cu2+ is 0. 11 ? smaller than Zn2+. By considering both pH and contact time factors, this study shows that by adjusting the pH of Zn2+ solutions to a minimum pH value of 7, the contact time required to achieve maximum Zn2+ removal rate was 90%, which can be achieved within 60 min. Meanwhile, zeolite performed better in Cu2+ removal without any pH adjustment where a maximum of 94% was achieved at 120 min. Final concentration of 0.523 mg/L Cu2+ and 0. 981 mg/L Zn2+ were obtained in this study. Kinetic study showed that Ritchie \' s equation predicted Cu2+ adsorption the best, while Zn2+ adsorption could be represented by Elovich model. This suggested that the adsorption on the activate site governed Cu2+and Zn2+removal process. Hence, future work should focus on modifying zeolite surface to improve the adsorptive performance.
其他文献
针对无人机在航拍目标跟踪的复杂场景过程中,运动目标可能会被遮挡或不确定跟踪,导致视觉模型出现逐渐损坏、漂移和不可逆转失败等问题,提出了一种无人机航拍目标的长期跟踪算法.首先,进行互补分类器多特征自适应融合设计,在贝叶斯分类器中采用颜色直方图特征,在相关滤波器中采用方向梯度直方图、灰度以及颜色名特征;结合多种特征的优点,构建目标鲁棒性的外观以适应复杂场景.然后,在相关滤波器中加入自适应时空正则化项.在空间正则化参数中引入局部变化,实现学习时限制像素可信度较低的滤波器;而在时间正则化中,根据全局响应自适应地调
针对传统算法对高调频率线性调频(linear frequency modulation,LFM)信号进行参数估计时误差较大的问题,提出了一种基于新型离散分数阶傅里叶变换(discrete fractional Fourier transform,DFrFT)的LFM信号参数估计算法.新型DFrFT在传统离散算法的基础上引入一种新型尺度变换型量纲归一化方法,其归一化因子可随变换阶次的改变自适应变化.基于该新型DFrFT,本文建立了LFM信号参数估计算法的数学模型.首先,通过新型量纲归一化方法对待估计LFM信
The effect of the pore density of porous copper ( Cu) on brazed Cu/porous Cu was investigated. A filler with a composition of Cu-9. 0Sn-7. 0Ni-6. 0P ( Sn:Tin;Ni:Nickel;P:Phosphorus) and porous Cu with pore densities of 15 pores per inch ( PPI) , 25 PPI, a
车对车(V2V)通信是智能交通系统的重要组成部分.隧道是智能交通系统的一个重要应用场景.考虑到隧道壁反射、车辆衍射以及隧道附属设施布置密而复杂的问题,研究隧道场景下的V2 V信道传播特性对于智能交通系统的设计与测试具有重要意义.本文利用宽带信道探测器对隧道环境下的V2 V信道进行了测量.测量所使用的载波频率和带宽分别为5.2 GHz和120 MHz.根据不同的情况,将测量分为3种类型:可视距(LOS)、部分视距(OLOS)和不可视距(NLOS).基于实际测量数据,建立不同场景的路径损耗模型和接收信号幅值衰
In this paper, battery aging diversity among independent cells was studied in terms of available capacity degradation. During the aging process of LiFePO4 batteries, the phenomenon of aging diversity can be observed. When batteries with same specification
在拉深成形过程中,纤维金属层板常见的失效模式主要有起皱、纤维拉伸断裂以及界面分层.受金属拉深成形测试的启发,经研究,当纤维金属层板以纤维拉伸断裂与界面分层失效为主要的失效模式时,可以将纤维应变引入到成形极限图中.但是,由于用于拉深测试的传统金属条状试样形状会干扰纤维金属层板内纤维应变的计算,因此,本研究设计了一种新型切槽形状试样.通过对比传统的条状试样和新型切槽试样的成形试验以考察玻璃纤维/聚酰胺树脂(Gf/PA)复合材料-铝合金层板的成形性能.研究结果表明:所设计的新型切槽试样可以将纤维计算的应变水平控
针对现有频谱分离方法进行声学场景分类研究时其分类准确率不高的问题,提出了一种基于梅尔频谱分离和长距离自校正卷积神经网络(long-distance self-calibration convolutional neural network,LSCNet)的声学场景分类方法.首先,介绍了频谱的谐波打击源分离原理,提出了一种梅尔频谱分离算法,将梅尔频谱分离出谐波分量、打击源分量和残差分量;然后,结合自校正神经网络和残差增强机制,提出了一种长距离自校正卷积神经网络;该模型采用频域自校正算法以及长距离增强机制来保
Variability of power generation due to the prevalence of cloud cover over solar photovoltaics (PV) power plants is a challenge faced by grid operators and independent system operators (ISOs) in the integration of solar energy into the grid. Solar forecast
为研究新型双箱型空腹圆弧钢拱的平面内稳定特性,采用理论推导与有限元数值模拟相结合的方法,研究其平面内弹性屈曲及弹塑性稳定承载力,分析剪力对拱截面破坏模式的影响,并建立了平面内稳定承载力的设计方法.首先,根据拱截面的剪力分布情况,研究了双箱型空腹圆弧钢拱截面整体剪切变形及弦腹杆剪切变形对平面内弹性屈曲的影响;推导出了考虑双剪切变形影响时,双箱型空腹圆弧钢拱的纯压弹性屈曲荷载公式.然后,参考轴心受压柱设计原理,引入稳定系数及正则化长细比,绘制了纯压状态下的稳定曲线.最后,分析了在几种常见荷载工况下,双箱型空腹
To solve the dead-zone in the output flow curve of the proportional flow valve without displacement sensor, a dead-zone compensation approach is proposed in this paper. Instead of detection and feedback of the valve spool position, the proposed approach a