Removal of nutrients from water by modified Bulgarian clinoptilolite

1. Removal of nutrients from water by modified Bulgarian clinoptilolite Nadejda Taneva, Grigor Mihailov University of Architecture, Civil Engineering and Geodesy Sofia, Bulgaria

2. Basic points • Characteristics of natural Bulgarian clinoptilolite • Influence of • contact time • depth and section of filter bed • water flow mode • clinoptilolite grain size on nutrients removal effect

3. Computer simulation of clinoptilolite structure

4. Мodel of ion exchange in the structure of clinoptilolite

5. Some characteristics of natural Bulgarian clinoptilolite The clinoptilolite used for the investigations was extracted from Beli Plast deposit near the town of Kardjali, in the Rhodopi Mountains, Bulgaria Chemical composition Physical properties

6. Ion-exchange properties of clinoptilolite • High ion-exchange capacity towards cations The selectivity row of the used zeolite is: Cs+ > Tl+ > Rb+ > K+ > NH4+> Na+ >Ba2+ >Pb2+ > Sr2+ > Ca2+ > Fe3+ > Al3+> Hg2+, Ag+, Cu2+, Cd2+, Co2+ > Zn2+ > Mg2+ > Mn2+ • Relatively low capacity towards anions: PO43-, CrO42-, SO42-, NO3- , HS-

7. Used fraction of natural clinoptilolite 0,5 – 1,2 mm

8. Obtained modificationsCl-Na,Cl-Al, Cl-Fe, Cl-oleylamine

9. plexiglass ion-exchange column, d=2 cm.BV depth 23 cm1 BV=72 ml Laboratory scheme

10. Influence of contact time Breakthrough saturation curves of ammonium on Cl-Naas a function ofcontact time atinitial concentration 20 mg/l

11. 0,4 0,35 Tc=3,7 min Tc=5 min 0,3 Tc=7 min 0,25 C/Co 0,2 0,15 0,1 0,05 0 0 20 40 60 80 100 120 140 BV Breakthrough saturation curves of phosphates on Cl-Al as a function of contact time at initial concentration 5 mg/l

12. Breakthrough saturation curves of phosphateson Cl-Feas a functionof contact timeat initial concentration 5 mg/l

13. 0,2 0,18 0,16 Tc=3,7 min 0,14 Tc=5 min 0,12 Tc=7 min C/Co 0,1 0,08 0,06 0,04 0,02 0 0 20 40 60 80 100 BV Breakthrough saturation curves of phosphates on Cl-oleylamineas a function ofcontact timeat initial concentration 5 mg/l

14. Effect of depth and section of filter bed Breakthrough saturation curves of phosphates on Cl-Alas a function of filter bed depth at initial concentration 5 mg/l and contact time 5 min.

15. Breakthrough saturation curves ofphosphateson Cl-Al as a function of filter bed diameter at initial concentration 5 mg/l and contact time 5 min

16. Effect of water flow mode Breakthrough saturation curves of ammonium on Cl-Na as a function ofwater flow mode at initialconcentration 20 mg/land contact time 3,5 min.

17. Breakthrough saturation curves of phosphates on Cl-Alas a function of water flow mode at initial concentration 5 mg/l and contact time 5 min.

18. Effect of clinoptilolite grain size Breakthrough saturation curves of phosphates on Cl-Alas a function of filter bed grain size at initial concentration 5 mg/l and contact time 5 min.

19. Conclusions • The optimal contact time for Cl-Na modification is 3,5 min. (linear velocity 0,7 m/h) • The alumina modification has the best adsorption capacity for phosphate ions andthe optimal contact time is 5 min. (linear velocity 0,5 m/h) • Adsorption and ion exchange are favoured by smaller diameter and bigger depth of filter bed. • Upflow mode leads to increase of the surface of clinoptilolite particles available for ion-exchange and in this way favours the process. • For the removal of phospate on Cl-Al it is better filtration to be in downflow mode which favours the processes of adsorption and precipitation.

20. Thank you for your attention