Sorption of Ni2+ by different synthetic hydroxyapatite

Two hydroxyapatite (HAP) samples of different crystallinity were studied as a nickel immobilization matrix. Sorption isotherms were obtained by batch equilibration method, in the concentration range 1. 10-4 – 8. 10-3 mol/dm3 . Low crystalline sample has sorption capacity of 0.212 mmol/g, and due to its higher specific surface area and lower Ca/P ratio it was found to be better sorbent for Ni2+ than crystalline HAP (0.092 mmol/g).Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Korelacija između fizičko-hemijskih svojstava hidroksiapatita i sorpcije jona Cu(II)

Izučavan je proces sorpcije Cu2+ jona iz vodenih rastvora sintetičkim hidroksiapatitnim (HAP) prahovima različitih fizičko-hemijskih svojstava. Određeni su maksimalni sorpcioni kapaciteti uzoraka, a stabilnost nagrađenih HAP-Cu proizvoda ispitana je u rastvorima kompetitvnog katjona i u kiseloj sredini. Uspostavljena je korelacija između sorpcionih i fizičkohemijskih svojstava HAP-a. Prahovi razvijene specifične površine i niže kristaličnosti pokazali su se kao efikasniji sorbenti, dok promena molskog Ca/P odnosa i tačke nultog naelektrisanja ispitivanih uzoraka nije bitno uticala na sorpciju jona Cu2+. Na osnovu molskih odnosa sorbovanih Cu2+ i otpuštenih Ca2+ jona, promena pH vrednosti rastvora i rezultata rendgenske difrakcione analize, diskutovani su glavni mehanizmi sorpcije Cu2+ jona HAP-om

The role of intraparticle diffusion in the sorption of Cu2+ ions onto hydroxyapatite

The Cu2+ sorption onto HAP was investigated as a function of time, in the concentration range 5·10-4 - 5·10-3 mol/dm3. The experimentally obtained kinetic data were fitted with the intraparticle diffusion model. The correlation coefficients were low considering the overall reaction period. However, q versus t0.5 plots could be divided into three segments, out of which the second linear segment can be attributed to the intraparticle diffusion. Intraparticle diffusion rate constants (ki) increased from 3.57·10-3 to 7.80·10-3 mmol/g min0.5 with the increase of the initial Cu2+ concentration. As the lines did not pass through the origin it was concluded that intrapaticle diffusion is not the only rate-controlling step.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Relationships Between Bone Treatment Conditions and Co2+ Sorption Capacities

Co-60 is an important radionuclide in spent nuclear fuel and liquid radioactive wastes. For the purification of water containing Co2+, ions sorption on hydroxyapatite (Ca-10(PO4)(6)(OH)(2)) can be applied. The process is particularly cost-effective if biological apatite from animal bones is utilized. In this study, dependence between bovine bone treatment conditions and Co2+, sorption was investigated as a function of initial metal concentration. Eight sorbents were previously prepared using fractional factorial design, by simultaneous variations of five process variables between two levels: factor A-the type of the chemical reagent (H2O2 or NaOH), factor B-reagent concentration (0.1 mol/L or 2 mol/L), factor C-reaction temperature (20(o)C or 60(o)C), factor D-contact time (1h or 3h) and factor E-sample annealing (without or at 400(o)C). At this point, the effects of treatment factors on Co2+, sorption efficiency were evaluated using statistical analysis. Amounts of Co2+ sorbed, amounts of released Ca2+ ions and final pH values were considered as system responses. The results showed that the impact of various treatment factors was different for different starting concentrations of Co2+. Consequently, no statistically important relations could be established between treatment conditions and Co2+, sorption from 10(-4) and 5*10(-4) mol/L solutions, whereas thermal treatment at 400(o)C was the only statistically significant factor influencing sorption from the most concentrated solution (5*10(-3) mol/L). Depending on initial Co2+, concentration, various factors had statistically significant effect on equilibrium pH values, whereas no relation was found between bone treatment conditions and the amounts of Ca2+, released during the sorption.3rd International Conference on Radiation and Applications in Various Fields of Research (RAD), Jun 08-12, 2015, Budva, Montenegr

The evaluation of radionuclides removal using clinoptilolite, hydroxyapatite and their mixtures

The sorption properties of clinoptilolite and hydroxyapatite towards Cs1+, Co2+, and Sr2+ ions were compared, under the same experimental conditions. Cs1+ was preferably sorbed by natural clinoptilolite. Conversely, synthetic hydroxyapatite exhibited higher sorption capacities for Co2+ and Sr2+, while the sorption of Cs1+ was negligible. It was shown that, as a consequence of different affinity towards investigated cations, application of mixed clinoptilolite/hydroxyapatite sorbent represents a good strategy for the purification of effluents containing a mixture of Cs1+, Co2+ and Sr2+.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Ispitivanje uticaja fizičko-hemijskih svojstava sorbenata koštanog porekla na imobilizaciju jona Co2+ i Sr2+

Cilj istraživanja predstavlja ispitivanje mogućnosti imobilizacije jona Co2+ i Sr2+ sirovim i tretiranim životinjskim kostima kao biosorbentom. Određivan je uticaj različitih tretmana (hemijske degradacije, degradacije na povišenim temperaturama) na fizičko-hemijska svojstva životinjskih kostiju. Za karakterizaciju uzoraka životinjskih kostiju korištene su standardne metode: termička analiza (TG-DTG-DTA), infracrvena spektroskopska analiza (IC), rendgenska difrakciona analiza (XRD), BET metoda određivanja specifične površine, određivanje tačke nultog naelektrisanja metodom uravnotežavanja, dok je atomska apsorpciona spektrometrija - AAS korištena za merenje koncentracije jona metala. Na osnovu fizičko-hemijskih analiza biosorbenata, kao i poređenja kapaciteta i mehanizama imobilizacije jona Co2+ i Sr2+, uspostavljene su korelacije između različitih tretmana, strukture i sorpcionih svojstava

Copper sorption capacity of the soil treated with unconventional alkalizing agents

The influence of unconventional alkaline additives (ground seashells and bauxite residue) on the copper (Cu) sorption and retention capacity of acidic soil was investigated. The soil collected near the mining and metallurgical complex in Bor (Serbia) was treated with different doses of additives, and the Cu sorption and desorption were assessed in batch conditions. The waste-derived materials proved to be efficient and sustainable alternatives to conventional alkalizers, increasing the maximum sorption capacity for Cu in correspondence with the soil pH increase. Nevertheless, added Cu was largely mobilized by weak acid extraction, demonstrating the importance of maintaining optimal soil pH for Cu leaching prevention

Comparative assessment of zinc ions sorption and retention by prospective unconventional soil additives

Mining, combustion of coal and waste, and steel processing are the main industrial activities that trigger the emission of large amounts of Zn, which reach the soil and pose a risk to its services, functions, and groundwater quality. A frequently associated process is soil acidification, reducing soil's ability to retain incoming toxic metals. The soil treatments with reactive, low-cost, and locally available materials might be a straightforward approach to decreasing the mobility of toxic metals and alleviating the environmental risks. This study aimed to compare Zn ions sorption and retention by several unconventional soil additives (seashell waste, bone char, and red mud) against the performance of acidic soil. Batch experiments of Zn ions sorption were initially performed using solutions with different Zn concentrations, followed by the determination of sorbed Zn stability in an acidic medium. The waste materials exhibited higher pH values and superior Zn sorption capacities with respect to the soil. The desorption experiment exposed different mechanisms of Zn ions fixation by studied materials. While the substantial amounts of Zn sorbed by seashells, red mud, as well as soil were released in the scope of the ion exchange and carbonate fraction, sensitive to pH decrease, the bone char preserved Zn in more stable fractions. The investigated waste materials can potentially prevent Zn leaching through the soil profile, with the bone char demonstrating the most significant capability for long-term retention performance

New materials for separation of radioactive strontium from the sea water

Otpuštanje 90Sr umora i okeane kao posledica testiranja nuklearnog naouružanja i akcidenata u nuklearnim objektima podstaklo je razvoj novih, jednostavnijih i bržih metoda i materijala za njegovu separaciju. Monitoring morske vode u slučaju akcidentnesituacije, kao i dekontaminacija tečnog otpada koji sadrži morsku vodu, predstavljaju izuzetno zahtevne zadatke usled složenog hemijskog sastava i visokog saliniteta matriksa. U ovom radu dat je pregled najnovijih rezultata u oblasti razvoja materijala sapotencijalom selektivnog vezivanja Sr-jona iz morske vode. Diskutovani su mehanizmi vezivanja i performanse različitih materijala sa aspekta primene u praksi i perspektivnih pravaca budućih istraživanja.The release of 90Sr into the sea and oceans as a result of testing nuclear weapons and accidents in nuclear facilities has prompted the development of new, simpler and faster methods and materials for its separation. The monitoring of seawater in the event of an accident, as well as decontamination of liquid waste containing sea water, represent extremely demanding tasks due to the complex chemical composition and high salinity of the matrix. This paper presents an overview of the latest results in the field of material development with the potential for selective binding of Sr-ions from seawater. Mechanisms of binding and performance of different materials are discussed from the aspect of an application in practice and directions of future research.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј

Leaching kinetics of Co(II) and Sr(II) contaminated soil via chemical extraction method

Artificially contaminated soil, with mixture of Co(II) and Sr(II) ions in different proportions, was tested. The main aim was to investigate the possibility of ethylenediamine-tetraacetic acid (EDTA) utilization in the chemical extraction process as a method for soil remediation in the case of mixed contamination. The efficiency of this process when EDTA of 10 -4 molL -1 was used was low, while the application of the EDTA solution of the initial concentration 5 · 10 -3 molL -1 or higher showed almost the same efficiency. This suggested that the application of the solution EDTA (5 · 10 -3 molL -1 ) is optimal from the aspect of cost and degradation of soil properties. Furthermore, process kinetic was fitted using one parameter shrinking core models. Kinetic data modeling showed that the process is complex, demanding multi resistance kinetic model. © 2018, Vinca Inst Nuclear Sci. All rights reserved