ساخت غشاي تبادل كاتيوني جهت جداسازي انتخابي يون ليتيم با استفاده از فرآيند الكترودياليز

چكيده انگليسي :

AbstractThe main subject of this thesis was the recovery of lithium ions from a synthetic solution similar to ahighly concentration lithium bromide solution of absorber chillers contaminated with sodium ions To thisaim lithium selective cation exchange membranes CEMs for recovery of lithium via electrodialysisprocess were prepared To prepare the selective CEMs at first a lithium manganese oxide spinel typeadsorbent with high adsorption capacity and stability was synthesized via hydrothermal method Thestability of the adsorbent was enhanced by insertion of cobalt ions into the spinel structure of adsorbent By using Design Expert Software Expert 11 and response surface methodology the optimumconditions for synthesis of adsorbent were obtained by simultaneous maximizing of the adsorptioncapacity and structural stability of the adsorbent At the optimum conditions the adsorbent showedadsorption capacity of 53 5 mg g high molar selectivity of 90 3 for lithium ions relative to sodium ions and high structural stability The adsorbent synthesized at the optimum conditions was characterized byXRD and BET analyses In the next step a heterogeneous cation exchange membrane was prepared byusing powdered Purolite cation exchange resin and polyethersulfone polymer Characterization of theheterogeneous cation exchange membranes showed that the synthesized membrane had bettercharacteristics of lithium flux selectivity and electrical resistance rather than CMH PES the commercialheterogeneous cation exchange membranes made by Ralex company Then the home made heterogeneousCEM was modified by placing the lithium selective spinel type adsorbent prepared in the first part of thework on the top surface of the membrane by using in situ polymerization method Optimization of thesurface modification conditions to achieve simultaneous maximized values for the lithium flux andselectivity in the two cell electrodialysis setup at at constant voltage of 5 volts was carried out At theoptimum conditions the lithium ion flux of 0 15 mol min 1 m 2 and the lithium molar selectivity of 32 2were obtained Also surface modification was performed on a FUJIFILM VI CEM commercialhomogeneous cation exchange membrane with the modification conditions optimized for the home madeheterogeneous CEM To modify the commercial homogeneous CEM the surface of the membrane wasinitially chlorinated by using thionyl chloride to give an acceptable adhesion and bonding of acrylic acidto the surface ATR FTIR FE SEM EDS and SEM analyses were used to confirm the modification ofthe homogeneous CEM The modified homogeneous CEM has lithium flux of 0 2 mol min 1 m 2 and thelithium molar selectivity of 78 1 Also other characteristics including membrane thickness water content IEC membrane potential transport number permselectivity and electrical resistance were determined forall of the synthesized and modified CEMs Finally some experiments were designed and conducted byusing a three compartment ED cell equipped with the modified homogeneous CEM and an anionexchange membrane FUJIFILMVI AEM to simultaneously achieve to the highest amount of lithiumflux and molar selectivity of lithium At the optimum conditions the lithium ion flux of 0 29 mol min 1 m2and the lithium molar selectivity of 95 4 was obtained At these conditions after 360 min the cathodesolution had a lithium ion purity of 99 was achieved from a highly contaminated feed solution

بذرگر بجستاني، مجيد

ساخت غشاي تبادل كاتيوني جهت جداسازي انتخابي يون ليتيم با استفاده از فرآيند الكترودياليز

سردكن‌هاي جذبي , ليتيم , جاذب اسپينلي , غشاي تبادل كاتيوني انتخاب پذير , اصلاح سطح , الكترودياليز