Adsorption of Humic Acid from Water Using Chemically Modified Bituminous Coal-based Activated Carbons

Humic acid (HA) impairs water quality due to its reactivity with many substances present in water. During the drinking-water treatment process and water distribution via water supply system, HA present in water may react with chlorine and other disinfects producing harmful disinfection by-products (DBPs), which are categorized by the International Agency for Research on Cancer (IARC) in groups 2A (probably carcinogenic to humans) or 2B (possibly carcinogenic to humans). Several studies have investigated and reported increased HA removal by iron-coated sorbents. Therefore, the aim of this study was to examine the removal of HA from water by two commercially available bituminous coal-based activated carbons (ACs), Cullar D (Cm) and Hydraffin 30N (Hm). Prior to testing the chosen adsorbents were chemically modified according to two protocols: (1) oxidation by acid mixture (m1), and (2) oxidation with acid mixture followed by iron-ions impregnation (m2). The batch adsorption tests were used to test their efficiency in HA removal under various values of process parameters (initial HA concentration, pH, contact time, adsorbent mass, and temperature). The results showed that up to 96 % of HA removal can be obtained by Cullar D modification Cm1, while maximum uptake of HA by Hydraffin 30N modification was achieved with Hm1 (62.1 %). After surface saturation with Fe3+ –ions (m2), both activated carbons showed similar and lower performances in HA removal (Cm2 up to 66.5 %, and Hm2 up to 50.3 %). FTIR analysis confirmed differences in modified AC structures, as well as favorable structure of Cm1 for HA adsorption. This work is licensed under a Creative Commons Attribution 4.0 International License

Scientific opinion on labeling of natural mineral water can have a laxative effect and can have a diuretic effect

In accordance with Regulation on natural mineral, natural spring and table waters (Official Journal no. 81/13), labelling of natural mineral water with claim "can have a laxative effect" and "can have a diuretic effect", require conditions under which this claims can be used. These conditions must meet certain microbiological and physicochemical parameters. Setting microbiological and physicochemical parameters are based on the standards of the Codex Alimentarius Commission (Codex Stan 108-1981-rev. 1997) for natural mineral water, Croatian Regulation on natural mineral, natural spring and table waters (Official Journal no. 81/13), and data available from the literature. Presence of certain chemical elements or their compounds in certain concentrations in mineral water can cause a laxative or diuretic effect. Based on the available scientific literature, the Working group of Croatian Food Agency for issuing scientific opinion on labeling of natural mineral water „can have a laxative effect" and "can have a diuretic effect", concluded as follows: - researches indicate that the laxative effect was observed at the consumption of mineral water with sulphate proportions above 1000 mg / L - researches indicate that the diuretic effect was observed at the consumption of mineral water with lower proportions of minerals (less than 500 mg / L) - with regard to the perceived adaptation of the human body, increased shares of sulfate, and reduced content of minerals in mineral water, which ultimately induce the lack of occurrence of both of the above mentioned effects, Working Group recommends establishing the Commission within the relevant institutions (Ministry of Agriculture) to review each individual requirements for the use of statements "may have laxative effects" and "may have a diuretic effect"

Changes in the Lower Drava River Water Quality Parameters Over 24 Years

The goal of this study was to analyse 13 physico-chemical and microbiological parameters of the Drava River water at three sampling sites in the lower Drava region (eastern Croatia) over two distinct periods: the pre-war period between 1985 and 1992 and the post-war period between 1993 and 2008. Over both periods, most parameters kept within the tolerable water quality limits, while NO3-N, NH4-N and BOD5 were higher. The lower Drava showed slight organic pollution with high concentrations of dissolved oxygen. High levels of total coliforms and heterotrophic bacteria in the post-war period were only found downstream of the town of Osijek. Upstream of Osijek, the river showed a tendency for improvement.prostornih i vremenskih promjena tijekom perioda od 24 godine. Analizirali smo 13 fi zikalno-kemijskih i mikrobioloških parametara vode rijeke Drave na tri mjerne postaje smještene na području donjeg toka Drave (istočna Hrvatska) tijekom dvaju različitih razdoblja: 1985.-1992. (period prije rata) i 1993.-2008. (period poslije rata). Iako su vrijednosti većine podataka prikupljenih tijekom dvaju promatranih razdoblja oscilirale, vrijednosti su im se još uvijek nalazile u granicama za I. i II. vrstu voda. Vrijednosti nekih fi zikalno-kemijskih varijabla, kao što su NO3-N, NH4-N i BPK5 još su uvijek iznad granice za II. vrstu. Rezultati ovog istraživanja pokazali su blago organsko onečišćenje vode rijeke Drave s visokim koncentracijama otopljenog kisika. Povećanje broja ukupnih koliformnih i heterotrofnih bakterija u poslijeratnom razdoblju veliki je problem u području nizvodno od Osijeka pri čemu njihov broj katkad dostiže i vrijednosti za V. skupinu površinskih voda. Rezultati analize kvalitete vode rijeke Drave u dva različita razdoblja na dva mjerna mjesta uzvodno od Osijeka upućuju na tendenciju poboljšanja, iako neki od promatranih parametara pokazuju vrijednosti više od onih za II. skupinu riječnih voda. Različitosti, odnosno sličnosti među mjernim postajama istražene su metodom klasterske analize