Heavy metals removal by chemical coagulation and precipitation

Charerntanyarak, Lertchai

doi:10.2166/wst.1999.0642

Cited by 349 publications

(139 citation statements)

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“…At higher pH, ashes could act as a precipitant agent similarly to lime, which is used in chemical precipitation of heavy metals from inorganic effluent. In the case of removal of Zn(II), Cd(II), Mn(II), Mg(II) from the waste water with the use of lime, hydroxides are precipitated at elevated pH, but values of pH 9.5 or greater are necessary for the effective removal (Charerntanyarak, 1999). Similarly to lime or calcium hydroxide, which are the most commonly employed precipitant agents, ash could be also applied in wastewater treatment to precipitate heavy metal ions, because of the alkalization properties.…”

Section: Mechanism Of the Metal Ions Removal By Ashesmentioning

confidence: 99%

Using wood and bone ash to remove metal ions from solutions

Chojnacka

Michalak²

2013

Global NEST Journal

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In the present work, wood and bone ash were used to remove metal cations from solutions. Cation-removal capacity of the ashes was analyzed by potentiometric titration. It was found that the capacity of wood ash was two times higher (37.3 meq g ). Kinetics of metal ions removal by both ashes was described with pseudo-second order equation and Langmuir model was employed to describe equilibrium of the process. Wood ash had better removal properties than bone ash -at the same experimental conditions biosorption capacity at equilibrium for wood ash was 2 times higher (244 mg g . Promising results were also obtained for wood ash, which was capable of removing 67.9 % of Zn(II) ions, 70.4 % of Cd(II) ions, 92.8 % of Cu(II) ions and 99.1 % of Cr(III) ions from model solution of wastewater from metallurgical industry and 84.5 % of Cr(III) ions from the postbiosorption solution from the production process of biological feed additives. The utilization of ashes of biological origin was found to be a promising alternative to conventional processes of wastewater treatment.

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Section: Mechanism Of the Metal Ions Removal By Ashesmentioning

confidence: 99%

Using wood and bone ash to remove metal ions from solutions

Chojnacka

Michalak²

2013

Global NEST Journal

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“…Thus, elimination of heavy metals is of vital importance to environmental and health organizations. Various processes have been employed for heavy metal removal from effluents and waste-water including: chemical coagulation and precipitation [1], reverse osmosis [2], ion exchange [3], adsorption [4], ultrafiltration [5] and others. Of these processes, adsorption is the most effective technique for removing heavy metals [6].…”

Section: Introductionmentioning

confidence: 99%

Removal of cobalt(II) from aqueous solution by local Saudi bentonite: Kinetic and equilibrium investigations

Al-Duaij

Attia

Khezami

et al. 2016

Maced. J. Chem. Chem. Eng.

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Natural bentonite clay from Saudi Arabia was used to remove cobalt from aqueous solution. The clay samples were first characterized for their chemical composition and structure. Batch sorption studies were then conducted to assess their capacity to remove cobalt. The effect of contact time, initial analyte concentration, bentonite dose and temperature on the adsorption was investigated. The results showed that equilibrium was attained in 60 minutes. The metal adsorption was fitted to a Langmuir isotherm model and the maximum monolayer adsorption capacity was found to be 19.85 mg g −1 at 333 K. The pseudosecond-order kinetic model provided the best correlation to the experimental data. The application of an intra-particle diffusion model revealed that the adsorption mechanism of the cobalt ions is a rather complex process and that diffusion is involved in the overall rate of the adsorption process, but it is not the only rate-controlling step. The activation energy, E a , ranged between 4.33 and 9.14 kJ mol −1 , indicating a physical adsorption process.Keywords: bentonite; cobalt; kinetics; equilibrium ОТСТРАНУВАЊЕ НА КОБАЛТ(II) ОД ВОДНИ РАСТВОРИ СО ЛОКАЛЕН САУДИСКИ БЕНТОНИТ: КИНЕТИЧКИ И РАМНОТЕЖНИ ИСТРАЖУВАЊАПриродната бентонитна глина од Саудиска Арабија беше употребена за отстранување на кобалт од водни растврори. Глинените примероци прво беа карактеризирани преку хемиска анализа и структура. Потоа беа спроведени сорпциски истражувања со цел да се процени нивниот капацитет за отстранување на кобалт. За атсорпцијата беа испитувани ефектот на времето на дејството, почетната концентрација на аналитот, бентонитната доза и температурата. Резултатите покажаа дека рамнотежата се постигнува за 60 минути. Атсорпцијата на металот беше усогласена со изотермен модел на Langmuir и беше определено дека максималниот монослоен капацитет изнесува 19,85 mg g −1 на 333 K. Најдобра корелација беше постигната со кинетички модел од псевдо-втор ред. Примената на дифузиски модел на интра-честички откри дека атсорпцискиот механизам на јоните на кобалт е доста сложен процес и дека вклучува дифузија во севкупната брзина на атсорпцискиот процес, но не е чекорот што ја контролира брзината. Активациската енергија, E a , се движи од 4,33 до 9,14 kJ mol −1 што укажува на физички атсорпционен процес.

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“…Many conventional methods are available for the treatment of metal-bearing effluent such as electrochemical [7], biological treatment [8], membrane separation [9], coagulation [10], chemical precipitation [11], reverse osmosis [12], solvent extraction [13], and ion exchange [14]. However, the application of such methods is often limited, particularly in handling effluents containing trace amounts of heavy metal ions (1-100 mg/l) due to incomplete metal removal, energy-intensive, economically expensive, and generation of secondary waste products (e.g.…”

Section: Introductionmentioning

confidence: 99%