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.

/pdf/adsorption-of-fluoride-from-water-solution-on-bone-char-2xjff2bkrx.pdf

Adsorption of Fluoride from Water Solution on Bone Char

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.

Generation of sulfate radical through heterogeneous catalysis for organic contaminants removal: Current development, challenges and prospects

https://dr.ntu.edu.sg/bitstream/10356/96770/1/30.%20Application%20of%20Layered%20Double%20Hydroxides%20for%20Removal%20of%20Oxyanions.pdf

Application of layered double hydroxides for removal of oxyanions: A review

The Metabolic Consequences of Sleep Deprivation

Chitosan microspheres as a potential carrier for drugs

Removal of phosphate by aluminum oxide hydroxide.

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

Removal of lead ions in drinking water by coffee grounds as vegetable biomass.

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.

Adsorption of fluoride ions onto carbonaceous materials

Adsorption of dyes onto carbonaceous materials produced from coffee grounds by microwave treatment.

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.

Seiki Tanada

Papers

Removal of phosphate by aluminum oxide hydroxide.

Removal of lead ions in drinking water by coffee grounds as vegetable biomass.

Adsorption of fluoride ions onto carbonaceous materials

Adsorption of dyes onto carbonaceous materials produced from coffee grounds by microwave treatment.

Removal of Formaldehyde by Activated Carbons Containing Amino Groups.