This paper reports a simple, facile and rapid preparation of 3‑mercapto‑propanoic acid (MPA) modified cellulose filter paper (MPA-Cell paper) for arsenate removal from drinking water. The MPA was covalently grafted to the cellulose filter paper (Cell) by esterification process through the formation of O‑acylisourea intermediate and characterized by the FTIR, SEM, EDS and XPS analyses. The arsenate adsorption efficiency was studied for batch and semi-continuous systems while exploring the adsorption kinetics, isotherm and the effect of pH for the former. The experimental data fitted well with Langmuir, Dubinin-Radushkevich (DR) and pseudo second order kinetic models. The mechanism of adsorption was studied by FTIR spectroscopy utilizing the adsorption isotherm, kinetic model and XPS results. The modified filter paper performed well at nearly neutral pH in arsenate removal through adsorption and demonstrated a significant arsenate uptake capacity of 92.59 mg/g. The DR and FTIR results indicated that the adsorption of arsenate ion occurred through ion exchange process. The MPA-Cell paper could have a potential use as low-cost but efficient commercial adsorbent for arsenate abatement from contaminated drinking water by both batch as well as semi-continuous operating systems. The MPA-Cell paper could purify ground water containing high level of arsenate.
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http://dx.doi.org/10.1016/j.ijbiomac.2018.10.065 | DOI Listing |
In the field of image processing, optical neural networks offer advantages such as high speed, high throughput, and low energy consumption. However, most existing coherent optical neural networks (CONN) rely on coherent light sources to establish transmission models. The use of laser inputs and electro-optic modulation devices at the front end of these neural networks diminishes their computational capability and energy efficiency, thereby limiting their practical applications in object detection tasks.
View Article and Find Full Text PDFOptical transceivers serve as the backbone of high-speed data transmission over optical fiber in communication systems and there is a constant challenge to keep cost and power consumption low while increasing data capacities. However, dispersion impairments introduced by the transmission of data over optical fiber, limit the baud rates and fiber reach. In this paper, we demonstrate a low loss, transmission-based grating device to compensate for dispersion up to 20 km by the concatenation of gratings where the operation occurs outside of the stopband in the region where transmissivity is high, and the normal dispersion magnitude is large.
View Article and Find Full Text PDFAn adaptive polarization controller (APC) is crucial in mitigating carrier fading in a self-homodyne coherent detection (SHCD) system. In this paper, we propose a simplified APC design based on the X-cut, Y-propagating lithium niobate platform. Meanwhile, the alpha-beta filter is used to control the designed APC.
View Article and Find Full Text PDFThis paper proposes an imaging technique to remove strong reflections from specular surfaces using polarization characteristics combined with light field imaging. Firstly, the correct strong reflection region is found by studying the reflected light characteristics, and the strong reflection region highlights are filtered out using Stokes parameters based on polarization information. Then, a system of microlens arrays with different transmittances was built for imaging, and the system was image-corrected to enable more information about the scene to be captured.
View Article and Find Full Text PDFAccurately estimating phase is crucial in continuous-variable quantum key distribution systems, directly impacting the final secret key rate. In previous systems that utilize the local local oscillator, phase estimation is closely tied to the amplitude and signal-to-noise ratio (SNR) of the pilot signal. As SNR decreases, so does the accuracy of phase estimation, leading to increased excess noise and a potential loss of the system's secret key rate.
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