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Author

Naohito Kawasaki

Other affiliations: University of Tokushima
Bio: Naohito Kawasaki is an academic researcher from Kindai University. The author has contributed to research in topics: Adsorption & Activated carbon. The author has an hindex of 23, co-authored 218 publications receiving 2641 citations. Previous affiliations of Naohito Kawasaki include University of Tokushima.


Papers
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Journal ArticleDOI
TL;DR: The result indicated that the hydroxyl groups on aluminum oxide hydroxide have selective adsorptivity for phosphate and could be used for the removal of phosphate from seawater.

346 citations

Journal ArticleDOI
01 Jan 2005
TL;DR: The present study gave an affirmative answer to the possibility of using coffee grounds, an abundant food waste, for removing lead ions from drinking water with increased concentration of perchloric acid used for treating them.
Abstract: In an attempt to reuse food waste for useful purposes, we investigated the possibility of using coffee grounds to remove lead ions from drinking water We studied the lead ion adsorption characteristics of coffee beans and grounds by measuring their fat and protein content, adsorption isotherms for lead ions, and adsorption rates for lead ions The number of lead ions adsorbed by coffee grounds did not depend on the kind of coffee beans or the temperature at which adsorption tests were performed The rate of lead ion adsorption by coffee grounds was directly proportional to the amount of coffee grounds added to the solution When coffee grounds were degreased or boiled, the number of lead ions decreased When proteins contained in coffee grounds were denatured, the lead ion adsorption was considerably reduced The lead ion adsorption capacity of coffee grounds decreased with increased concentration of perchloric acid used for treating them and disappeared with 10% perchloric acid The experiments demonstrated that proteins contained in coffee beans depend upon the adsorption of lead ion The present study gave an affirmative answer to the possibility of using coffee grounds, an abundant food waste, for removing lead ions from drinking water

209 citations

Journal ArticleDOI
01 Jul 2004
TL;DR: The mechanism of fluoride ion adsorption onto bone char is clearly chemical in nature because the amount of fluoride ions adsorbed onto boneChar increased with increasing temperature and decreasing pH, and was shown to depend on the concentration of sodium chloride in solution because of the "salting-out" effect.
Abstract: The characteristics of fluoride ion adsorption onto carbonaceous materials were derived as adsorption isotherms at different temperatures and in different pH solutions. The fluoride ion was adsorbed into pores in carbonaceous materials produced from wood; the larger the specific surface area, the more fluoride ions adsorbed. Bone char was the most effective adsorbent. The composition of bone char includes calcium phosphate, calcium carbonate, and so on. This suggests that the phosphate ion in bone char was exchanged with a fluoride ion. Moreover, the mechanism of fluoride ion adsorption onto bone char is clearly chemical in nature because the amount of fluoride ion adsorbed onto bone char increased with increasing temperature and decreasing pH. The amount of fluoride ion adsorbed onto bone char was also shown to depend on the concentration of sodium chloride in solution because of the "salting-out" effect. The adsorption of fluoride ion onto bone char is endothermic. Bone char can be utilized to remove fluoride ions from drinking water.

208 citations

Journal ArticleDOI
TL;DR: The microwave treatment would be useful for the carbonization of organic wastes to save energy and indicate that the adsorption of dyes depended upon the surface polar groups on the carbonaceous materials.

132 citations

Journal ArticleDOI
01 Jun 1999
TL;DR: The adsorbate was prepared by the amination of an activated carbon surface and the removal efficiency and the adsorption mechanism of formaldehyde onto the aminated activated carbon were studied.
Abstract: Formaldehyde has been used for disinfection and antisepsis in hospitals due to its bactericidal action, but it is toxic to humans. Hence, we developed adsorbates for the removal of formaldehyde. The adsorbate was prepared by the amination of an activated carbon surface. The removal efficiency and the adsorption mechanism of formaldehyde onto the aminated activated carbon were studied. The concentrated sulfuric acid and nitric acid treatment introduced nitro groups onto the surface of the activated carbon. The nitro groups were reduced by the reaction of powdered iron and hydrochloric acid to the amino groups. The amount of formaldehyde adsorbed onto the activated carbon increased with the amination of the activated carbon because of the increasing interaction between the surface of the activated carbon and the formaldehyde. Copyright 1999 Academic Press.

113 citations


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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: In this article, the effects of solution pH and temperature on the adsorption of fluoride onto bone char made from cattle bones were investigated, and it was found that the maximum adaption took place at pH 3.
Abstract: The effects of solution pH and temperature on the adsorption of fluoride onto bone char made from cattle bones were investigated in this work. It was found that the maximum adsorption took place at pH 3 and the adsorption capacity decreased nearly 20 times augmenting the pH from 3 to 12. This behavior was attributed to the electrostatic interactions between the surface of bone char and the fluoride ions in solution. The adsorption capacity was not influenced by temperature in the range from 15 to 35 °C. A comparison of fluoride adsorption capacities among several adsorbents revealed that the adsorption capacity of the bone char was 2.8 and 36 times greater than those of a commercial activated alumina (F-1) and a commercial activated carbon (F-400). The adsorption capacity is considerably dependent upon the physicochemical properties of the bone char surface and the solution pH.

1,865 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provide a state-of-the-art review on the development in heterogeneous catalysts including single metal, mixed metal, and nonmetal carbon catalysts for organic contaminants removal, with particular focus on peroxymonosulfate (PMS) activation.
Abstract: Sulfate radical-based advanced oxidation processes (SR-AOPs) employing heterogeneous catalysts to generate sulfate radical (SO4 −) from peroxymonosulfate (PMS) and persulfate (PS) have been extensively employed for organic contaminant removal in water. This article aims to provide a state–of–the–art review on the recent development in heterogeneous catalysts including single metal, mixed metal, and nonmetal carbon catalysts for organic contaminants removal, with particular focus on PMS activation. The hybrid heterogeneous catalyst/PMS systems integrated with other advanced oxidation technologies is also discussed. Several strategies for the identification of principal reactive radicals in SO4 −–oxidation systems are evaluated, namely (i) use of chemical probe or spin trapping agent coupled with analytical tools, and (ii) competitive kinetic approach using selective radical scavengers. The main challenges and mitigation strategies pertinent to the SR-AOPs are identified, which include (i) possible formation of oxyanions and disinfection byproducts, and (ii) dealing with sulfate produced and residual PMS. Potential future applications and research direction of SR-AOPs are proposed. These include (i) novel reactor design for heterogeneous catalytic system based on batch or continuous flow (e.g. completely mixed or plug flow) reactor configuration with catalyst recovery, and (ii) catalytic ceramic membrane incorporating SR-AOPs.

1,802 citations

Journal ArticleDOI
TL;DR: This review critically identifies the shortcomings in current research on LDHs, such as the common weaknesses in the adopted methodology, discrepancies among reported results and ambiguous conclusions.

1,445 citations

01 Dec 2007

1,121 citations