| Abstract (english) | The occurrence and concentrations of fluoride in surface and groundwater depend on pH, total dissolved solids, alkalinity, hardness, and geochemical composition of aquifers. However, in many countries, elevated fluoride concentration values are the result of fluoride-contaminated wastewater discharges. Because of fluoride pollution and the health problems that it causes, the World Health Organization (WHO) has set a maximum permissible fluoride content in drinking water of 1.5mgl<sup>–1</sup>.
There are different ways of removing elevated concentrations of fluoride from water, such as coagulation and precipitation, membrane processes, electrochemical treatments, ion-exchange and its modification, but the adsorption process is generally accepted as the cheapest and most effective method for removing fluoride from water.
Organic waste is increasing every day, especially in developed countries, and is generated in both industries and households. One of the ways to reduce such waste is the production of adsorbents for water defluorination. Adsorbents, most often prepared as activated carbon, can be obtained from various materials such as egg shells, fruit and vegetable peel, various leaves, stems, trunk bark, grain shells, legume shells, and many others.
The aim of this paper is to provide an overview of the latest research on the use of adsorbents obtained from organic waste materials in order to remove elevated concentrations of fluoride from water. |
| Abstract (croatian) | Pojavnost i koncentracije fluorida u površinskim i podzemnim vodama ovise o pH, ukupnoj otopljenoj krutoj tvari, alkalnosti, tvrdoći i geokemijskom sastavu vodonosnika, no u mnogim zemljama svijeta povišene vrijednosti koncentracije fluorida rezultat su ispuštanja otpadnih voda onečišćenih fluoridima. Zbog onečišćenja fluoridima i zdravstvenih problema koje ono uzrokuje Svjetska zdravstvena organizacija (WHO) odredila je najveći dopušteni sadržaj fluorida u pitkoj vodi od 1,5mgl<sup>–1</sup>. Postoje različiti načini uklanjanja povišenih koncentracija fluorida iz vode, kao što su koagulacija i taloženje, membranski procesi, elektrokemijski tretmani, ionska izmjena i njezina modifikacija, ali je adsorpcijski proces općenito prihvaćen kao najjeftinija i najučinkovitija metoda. Količina organskog otpada svakim je danom sve veća, posebice u razvijenim zemljama, a stvara se kako u industriji tako i u kućanstvima. Jedan od načina smanjenja takvog otpada je proizvodnja adsorbensa za defluorizaciju vode. Adsorbensi, najčešće pripremljeni kao aktivni ugljen, mogu se dobiti od raznih materijala, kao što su ljuske jajeta, kore voća i povrća, razni listovi, stabljike, kora debla, ljuske žitarica, ljuske mahunarki i mnogi drugi.
Cilj ovog rada je dati pregled najnovijih istraživanja o uporabi adsorbensa dobivenih iz organskog otpada za uklanjanje povišenih koncentracija fluorida iz vode. |
