The adsorption of copper ions from synthetic aqueous solutions on natural zeolite (clinoptilolite) was examined. In order to determine the rate of adsorption and the copper uptake at equilibrium, a series of experiments were performed under batch conditions from single ion solutions. Equilibrium data were evaluated based on adsorption (Langmuir and Freundlich) isotherms. The adsorption kinetics is reasonably fast. In the first 20 min of the experiment, approximately 80% of Cu 2+ ions is adsorbed from the solutions. Data obtained from the kinetic experiments have been described by the pseudo-second order kinetic model as well as by the Weber-Morris and Furusawa-Smith models.
The kinetics of manganese adsorption onto natural zeolite (clinoptilolite) was studied in terms of initial metal ion concentration and adsorbent mass. In order to select the main rate-determining step in the overall uptake mechanism, a series of experiments was performed under batch conditions from single ion solutions. Data obtained from the kinetic experiments are interpreted in terms of pseudo-second order kinetic model, Weber and Morris model and model proposed by Furusawa and Smith.The adsorption kinetics is reasonably fast. It means that in the first 20 min approximately 75% of Mn 2+ is adsorbed from solutions. From the kinetic data, it can be concluded that adsorption of manganese ions from solution by natural zeolite is more efficient at higher adsorbent mass and at lower manganese concentration in solution. The amount of Mn adsorbed on zeolite increases at higher manganese concentration in solution.From the kinetic models, it can be concluded that intraparticular diffusion is more likely to be the rate determining step, but at higher concentrations of Mn ions in solution, film diffusion may take a part in a rate determining step.Key words: manganese ions; adsorption; zeolite; kinetic ИСПИТУВАЊЕ НА КИНЕТИКАТА НА ОТСТРАНУВАЊЕTO НА МАНГАН ОД ВОДНИ РАСТВОРИ СО АТСОРПЦИЈА НА ПРИРОДЕН ЗЕОЛИТКинетиката на атсорпцијата на манган со природен зеолит (клиноптилолит) е испитувана во зависност од почетната концентрација на јони на манган во растворот и масата на атсорбентот. Со цел да се определи најбавниот чекор на реакцијата, преку кој би се определила вкупната брзина на реакцијата, изведени се серија експерименти во еднокомпонентни раствори. Добиените податоци се интерпретирани со: псевдо кинетичкиот модел од втор ред, моделот на Weber и Morris и моделот предложен од Furusawa и Smith.Резултатите покажуваат дека атсорпцијата се одвива релативно брзо. Тоа значи дека во првите 20 min околу 75% од јоните на манган во растворот се атсорбирани на клиноптилолитот. Од податоците од испитувањето на кинетиката може да се заклучи дека атсорпцијата на манга-новите јони е поефикасна при поголема маса на атсорбент и при пониска концентрација на манган во растворот. Количината на атсорбиран манган врз зеолитот се зголемува со порастот на концен-трацијата на јоните на манган во растворот.Од моделирањето на кинетиката може да се заклучи дека поверојатно е чекорот со кој се определува брзината на атсорпцијата да биде дифузијата во внатрешноста на честичката, но при повисоки концентрации на јони на манган во растворот за определување на чекорот може да се земе во предвид и филм-дифузијата.Клучни зборови: јони на манган; атсорпција; зеолит; кинетика Dedicated to Academician Gligor Jovanovski on the occasion of his 70 th birthday.A. Zendelska, M. Golomeova, K. Blažev, B. Boev, B. Krstev, B. Golomeov, A. Krstev Maced.
This chζpter discusses the ζdsorption of leζd ζnd zinc ions onto ζ nζturζl zeolite clinoptilolite ζnd zeolite beζring tuff stilbite from ζqueous solution, whereby the mζin pζrζmeters were the effects of initiζl pH of solution, mζss of ζdsorbent, ζnd initiζl metζl concentrζtion in solution.The physicζl ζnd chemicζl properties of the nζturζl mζteriζls used ζre chζrζcterized by X-rζy diffrζction, scζnning electron microscopy, energy-dispersive spectroscopy, ζnd "ES-ICP.Determinζtion of the mζximum cζpζcity of ζdsorbents for leζd ζnd zinc removζl under the studied conditions is the mζin objective of the equilibrium studies. Experimentζl dζtζ ζre fitted to the Freundlich ζnd Lζngmuir ζdsorption models.The ζdsorption of leζd ζnd zinc ions from diluted solution onto nζturζl zeolite ζnd zeolite beζring tuff occurs efficiently. Determinζtion of the impζct of the studied pζrζmeters on the efficiency of removζl of leζd ζnd zinc ions from the solution showed thζt in the studied rζnge, in the cζse of leζd ions, there were not ζny significζnt chζnges found, but in the cζse of zinc ions, removζl wζs most effective ζt lower concentrζtion of zinc ions, higher mζss of ζdsorbents, ζnd higher pH vζlue of the solution.
Background The skin is exposed to numerous particulate and gaseous air pollutants. The ones that need particular attention are the particles that adhere to the skin surface, which can later cause direct skin damage. This study aimed to characterize air pollution (AP) particles adhered to the human skin by using scanning electron microscopy (SEM) combined with X‐ray dispersive energy spectrometry (EDX). Methods Tape stripping was performed from six healthy volunteers exposed to urban AP to collect stratum corneum samples from the cheeks and forehead. The samples were analysed using SEM equipped with EDX system with a silicon drift detector at an accelerating voltage of 20 keV. After the preliminary examination, the particles were located and counted using 1000× magnification. Each particle was analysed, increasing magnification up to 5000× for precise dimension measurement and elemental composition analysis. At least 100 fields or a surface of approximately 1 mm2 were examined. Results Particles adhered to the skin were identified in all samples, with a particle load ranging from 729 to 4525. The average area and perimeter of all particles identified were 302 ± 260 μm2 and 51 ± 23 μm subsequently, while the equivalent circular diameter was, on average, 14 ± 6 μm. The particles were classified into ten groups based on morphology and elemental composition. Chlorides were the most numerous particle group (21.9%), followed by carbonaceous organic particles (20.3%), silicates (18%), carbonates (16.4%), metal‐rich particles (14%), and a minor number of bioaerosols, quartz‐like, and fly ash particles. Conclusion The SEM–EDX analysis provides evidence of the contamination of exposed skin to various airborne PM of natural or anthropogenic origin. This method may provide new insights into the link between exposure to AP and AP‐induced skin damage.
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