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.

Reversible logistics are complex to manage due to the uncertainty involved in the range of quality products, product return time, and return volume. The purpose of reversible logistics (RL) is to reduce the raw material, the material for reuse and to respect the environment, which fits into some activities and purposes of the circular economy (CE), although in a broader concept. The optimized reverse logistics (RL) demonstrated by world examples and different brands also lead to better supply chain visibility, leading to benefits. The optimized reverse logistics demonstrated by domestic examples case study 1 (for pellets) and case study 2 (for pallets) also lead to better supply chain visibility, leading to benefits. The studies explore the impact that decisions made in the supply chain phases have on the overall level of "circularity". Optimized reverse logistics produces financial benefits while positively impacting the environment and business culture. Optimized reverse logistics also leads to better supply chain visibility, leading to benefits such as cost savings, greater customer satisfaction, better customer retention, faster and better service and reduced losses, improved sense of reduction of brand and waste, and greater sustainability.

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Dangerous and hazardous flotation tailings dams can be source of endangering of living environment. In their normal work and also in case of damages incidents in flotation tailings dams can be caused by natural catastrophe in the area or malfunctions due to unreliable work. Harmful chemicals, which can get to living environment at damages, can cause endangering of ecological factors (soils, water, air) and through them the whole ecosystem of the area. The paper describes the incidents on the tailings dams of the nonferrous mine in the Republic of Macedonia.