Fluoride is the most abundant, highly electronegative and geogenic contaminant in groundwater worldwide. Among the water quality parameters, the fluoride ion is unique in that it is beneficial to health if its concent...Fluoride is the most abundant, highly electronegative and geogenic contaminant in groundwater worldwide. Among the water quality parameters, the fluoride ion is unique in that it is beneficial to health if its concentration in water is within a threshold value (1.0 - 1.5 mg/l) and is detrimental (>2 ppm) if present in excess (WHO, 2006). High fluoride levels in drinking water has become a critical health hazard of this century as it induces intense impact on human health including skeletal and dental fluorosis. The objective of this study was to evaluate the potential of nanoalumina-carbon nanotubes blend as a sorbent for the removal of excess fluoride from water. Batch studies were conducted to assess the influence of various operational parameters viz. pH, temperature, agitation time, adsorbent dosage and presence of interfering ions. From the studies, it was clear that the rate of adsorption was initially rapid and attains equilibrium gradually in about 100 min. The presence of interfering ions such as chlorides and sulphates has very little effect on fluoride removal by nanoalumina-carbon nanotubes blend. Analysis of the equilibrium data fitted the Langmuir and Freundlich isotherms very well. The results of the study appear to be quite promising in the sense that they demonstrate the capability of nanoalumina-carbon nanotubes blend for removing fluorides from drinking water.展开更多
This paper proposes modifications to the tradional Ceiling Bounce Model and uses it to characterize diffuse indoor optical wireless channel by analyzing the effect of transceiver position on signal propagation propert...This paper proposes modifications to the tradional Ceiling Bounce Model and uses it to characterize diffuse indoor optical wireless channel by analyzing the effect of transceiver position on signal propagation properties. The modified approach uses a combination of the tradional ceiling bounce method and a statistical approach. The effects of different transmitter-receiver separations and height of the ceiling on path loss and delay spread are studied in detail.展开更多
文摘Fluoride is the most abundant, highly electronegative and geogenic contaminant in groundwater worldwide. Among the water quality parameters, the fluoride ion is unique in that it is beneficial to health if its concentration in water is within a threshold value (1.0 - 1.5 mg/l) and is detrimental (>2 ppm) if present in excess (WHO, 2006). High fluoride levels in drinking water has become a critical health hazard of this century as it induces intense impact on human health including skeletal and dental fluorosis. The objective of this study was to evaluate the potential of nanoalumina-carbon nanotubes blend as a sorbent for the removal of excess fluoride from water. Batch studies were conducted to assess the influence of various operational parameters viz. pH, temperature, agitation time, adsorbent dosage and presence of interfering ions. From the studies, it was clear that the rate of adsorption was initially rapid and attains equilibrium gradually in about 100 min. The presence of interfering ions such as chlorides and sulphates has very little effect on fluoride removal by nanoalumina-carbon nanotubes blend. Analysis of the equilibrium data fitted the Langmuir and Freundlich isotherms very well. The results of the study appear to be quite promising in the sense that they demonstrate the capability of nanoalumina-carbon nanotubes blend for removing fluorides from drinking water.
文摘This paper proposes modifications to the tradional Ceiling Bounce Model and uses it to characterize diffuse indoor optical wireless channel by analyzing the effect of transceiver position on signal propagation properties. The modified approach uses a combination of the tradional ceiling bounce method and a statistical approach. The effects of different transmitter-receiver separations and height of the ceiling on path loss and delay spread are studied in detail.
