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Daim ntawv tshawb fawb no tshawb nrhiav cov teebmeem ntawm NH4+ cov khoom tsis huv thiab cov noob piv rau txoj kev loj hlob thiab kev ua tau zoo ntawm nickel sulfate hexahydrate nyob rau hauv kev txias tsis tu ncua crystallization, thiab tshuaj xyuas cov teebmeem ntawm NH4+ cov khoom tsis huv rau txoj kev loj hlob, cov khoom thermal, thiab cov pab pawg ua haujlwm ntawm nickel sulfate hexahydrate. Ntawm qhov tsis huv concentration qis, Ni2+ thiab NH4+ ions sib tw nrog SO42− rau kev khi, ua rau cov khoom siv crystal txo qis thiab kev loj hlob thiab nce lub zog crystallization activation. Ntawm qhov tsis huv concentration siab, NH4+ ions raug koom ua ke rau hauv cov qauv crystal los tsim cov ntsev complex (NH4)2Ni(SO4)2 6H2O. Kev tsim cov ntsev complex ua rau cov khoom siv crystal nce siab thiab kev loj hlob thiab txo lub zog crystallization activation. Qhov muaj ob qho tib si siab thiab qis NH4+ ion concentration ua rau lattice distortion, thiab cov crystals ruaj khov ntawm qhov kub txog li 80 °C. Tsis tas li ntawd, qhov cuam tshuam ntawm NH4+ cov khoom tsis huv rau txoj kev loj hlob crystal yog ntau dua li ntawm qhov piv noob. Thaum qhov concentration ntawm cov khoom tsis huv qis, qhov tsis huv yooj yim rau kev sib txuas rau ntawm cov siv lead ua; thaum qhov concentration siab, qhov tsis huv yooj yim rau kev sib xyaw rau hauv cov siv lead ua. Qhov piv ntawm cov noob tuaj yeem ua rau cov khoom siv lead ua ntau ntxiv thiab txhim kho qhov huv ntawm cov siv lead ua me ntsis.
Nickel sulfate hexahydrate (NiSO4 6H2O) tam sim no yog ib qho khoom siv tseem ceeb uas siv rau hauv ntau yam lag luam, suav nrog kev tsim roj teeb, electroplating, catalysts, thiab txawm tias hauv kev tsim khoom noj, roj, thiab tshuaj tsw qab. 1,2,3 Nws qhov tseem ceeb tab tom loj hlob nrog kev txhim kho sai ntawm cov tsheb fais fab, uas vam khom ntau rau cov roj teeb lithium-ion (LiB) nickel. Kev siv cov hlau nickel siab xws li NCM 811 xav tias yuav tswj hwm los ntawm xyoo 2030, ua rau muaj kev thov nickel sulfate hexahydrate ntau ntxiv. Txawm li cas los xij, vim muaj kev txwv ntawm cov peev txheej, kev tsim khoom yuav tsis ua raws li qhov kev thov loj hlob, tsim kom muaj qhov sib txawv ntawm kev muab khoom thiab kev thov. Qhov kev tsis txaus no tau tsa kev txhawj xeeb txog kev muaj peev txheej thiab kev ruaj ntseg ntawm tus nqi, qhia txog qhov xav tau kev tsim khoom zoo ntawm cov roj teeb nickel sulfate uas muaj kev ntshiab siab, ruaj khov. 1,4
Feem ntau, kev tsim cov nickel sulfate hexahydrate yog ua tiav los ntawm kev siv crystallization. Ntawm ntau txoj kev, txoj kev txias yog ib txoj kev siv dav dav, uas muaj qhov zoo ntawm kev siv hluav taws xob tsawg thiab muaj peev xwm tsim cov khoom siv huv siab. 5,6 Kev tshawb fawb txog kev siv crystallization ntawm nickel sulfate hexahydrate siv kev siv crystallization txias tsis tu ncua tau ua tiav zoo heev. Tam sim no, feem ntau cov kev tshawb fawb tsom mus rau kev txhim kho cov txheej txheem crystallization los ntawm kev ua kom zoo dua cov kev ntsuas xws li kub, txias npaum li cas, noob loj thiab pH. 7,8,9 Lub hom phiaj yog kom nce cov khoom siv crystal thiab kev huv ntawm cov siv lead ua tau txais. Txawm li cas los xij, txawm hais tias muaj kev kawm txog cov kev ntsuas no, tseem muaj qhov sib txawv loj hauv kev saib xyuas rau qhov cuam tshuam ntawm cov khoom tsis huv, tshwj xeeb tshaj yog ammonium (NH4 +), ntawm cov txiaj ntsig crystallization.
Cov khoom tsis huv ntawm ammonium yuav muaj nyob rau hauv cov kua nickel uas siv rau kev ua kom nickel crystallization vim muaj cov khoom tsis huv ntawm ammonium thaum lub sijhawm rho tawm. Ammonia feem ntau siv ua tus neeg sawv cev saponifying, uas tso cov khoom me me ntawm NH4 + hauv cov kua nickel. 10,11,12 Txawm hais tias muaj ntau yam khoom tsis huv ntawm ammonium, lawv cov teebmeem rau cov khoom siv lead ua xws li cov qauv siv lead ua, cov txheej txheem loj hlob, cov khoom siv thermal, kev huv, thiab lwm yam tseem tsis tau nkag siab zoo. Kev tshawb fawb tsawg ntawm lawv cov teebmeem yog qhov tseem ceeb vim tias cov khoom tsis huv tuaj yeem cuam tshuam lossis hloov pauv kev loj hlob ntawm cov siv lead ua thiab, qee zaum, ua haujlwm ua cov tshuaj tiv thaiv, cuam tshuam rau kev hloov pauv ntawm cov ntaub ntawv metastable thiab ruaj khov. 13,14 Yog li ntawd, kev nkag siab txog cov teebmeem no yog qhov tseem ceeb los ntawm kev lag luam vim tias cov khoom tsis huv tuaj yeem ua rau cov khoom zoo.
Raws li ib lo lus nug tshwj xeeb, txoj kev tshawb fawb no tsom mus tshawb nrhiav qhov cuam tshuam ntawm ammonium impurities rau cov khoom ntawm nickel crystals. Los ntawm kev nkag siab txog qhov cuam tshuam ntawm impurities, cov txheej txheem tshiab tuaj yeem tsim los tswj thiab txo lawv cov teebmeem tsis zoo. Txoj kev tshawb fawb no kuj tshawb nrhiav qhov sib raug zoo ntawm qhov concentration ntawm impurity thiab kev hloov pauv ntawm cov noob piv. Txij li thaum noob siv dav hauv cov txheej txheem tsim khoom, cov noob parameters tau siv hauv txoj kev tshawb fawb no, thiab nws yog qhov tseem ceeb kom nkag siab txog kev sib raug zoo ntawm ob yam no. 15 Cov teebmeem ntawm ob qho parameters no tau siv los kawm txog cov khoom siv lead ua, cov txheej txheem loj hlob ntawm crystal, cov qauv crystal, morphology, thiab purity. Tsis tas li ntawd, tus cwj pwm kinetic, thermal properties, thiab cov pab pawg ua haujlwm ntawm cov crystals nyob rau hauv kev cuam tshuam ntawm NH4 + impurities ib leeg tau tshawb nrhiav ntxiv.
Cov ntaub ntawv siv hauv txoj kev tshawb no yog nickel sulfate hexahydrate (NiSO 6H2O, ≥ 99.8%) muab los ntawm GEM; ammonium sulfate ((NH)SO, ≥ 99%) yuav los ntawm Tianjin Huasheng Co., Ltd.; dej distilled. Cov noob siv lead ua siv yog NiSO 6H2O, crushed thiab sieved kom tau txais qhov loj me me ntawm 0.154 hli. Cov yam ntxwv ntawm NiSO 6H2O tau qhia hauv Rooj 1 thiab Daim Duab 1.
Cov nyhuv ntawm NH4+ impurities thiab noob piv rau crystallization ntawm nickel sulfate hexahydrate tau tshawb nrhiav siv kev txias tsis tu ncua. Tag nrho cov kev sim tau ua ntawm qhov kub pib ntawm 25 ° C. 25 ° C tau xaiv ua qhov kub crystallization xav txog cov kev txwv ntawm kev tswj kub thaum lub sijhawm lim. Crystallization tuaj yeem tshwm sim los ntawm kev hloov pauv kub sai sai thaum lub sijhawm lim cov tshuaj kub siv lub raj mis Buchner kub qis. Cov txheej txheem no tuaj yeem cuam tshuam rau kinetics, impurity uptake, thiab ntau yam khoom siv crystal.
Cov kua nickel tau npaj ua ntej los ntawm kev yaj 224 g NiSO4 6H2O hauv 200 ml dej distilled. Qhov concentration xaiv sib raug rau supersaturation (S) = 1.109. Supersaturation tau txiav txim siab los ntawm kev sib piv qhov solubility ntawm cov siv lead ua nickel sulfate yaj nrog qhov solubility ntawm nickel sulfate hexahydrate ntawm 25 ° C. Qhov supersaturation qis dua tau xaiv los tiv thaiv kev crystallization spontaneous thaum qhov kub raug txo qis rau thawj zaug.
Qhov cuam tshuam ntawm NH4+ ion concentration rau ntawm cov txheej txheem crystallization tau tshawb xyuas los ntawm kev ntxiv (NH4)2SO4 rau hauv cov kua nickel. Cov NH4+ ion concentration siv hauv kev tshawb fawb no yog 0, 1.25, 2.5, 3.75, thiab 5 g/L. Cov tshuaj tau raug cua sov ntawm 60 °C rau 30 feeb thaum do ntawm 300 rpm kom ntseeg tau tias sib tov sib npaug. Cov tshuaj tau txias mus rau qhov kub xav tau. Thaum qhov kub txog 25 °C, ntau yam ntawm cov noob siv lead ua (cov noob piv ntawm 0.5%, 1%, 1.5%, thiab 2%) tau ntxiv rau hauv cov tshuaj. Cov noob piv tau txiav txim siab los ntawm kev sib piv qhov hnyav ntawm noob nrog qhov hnyav ntawm NiSO4 6H2O hauv cov tshuaj.
Tom qab ntxiv cov noob siv lead ua rau hauv cov tshuaj, cov txheej txheem crystallization tau tshwm sim ntuj. Cov txheej txheem crystallization kav ntev li 30 feeb. Cov tshuaj tau lim siv lub tshuab lim kom cais cov siv lead ua los ntawm cov tshuaj. Thaum lub sijhawm lim, cov siv lead ua tau ntxuav tas li nrog ethanol kom txo qhov ua tau ntawm recrystallization thiab txo qhov lo ntawm cov khoom tsis huv hauv cov tshuaj rau ntawm qhov chaw ntawm cov siv lead ua. Ethanol tau xaiv los ntxuav cov siv lead ua vim tias cov siv lead ua tsis yaj hauv ethanol. Cov siv lead ua lim tau muab tso rau hauv lub chaw kuaj mob ntawm 50 ° C. Cov kev ntsuas kev sim ntxaws ntxaws siv hauv kev tshawb fawb no tau qhia hauv Rooj 2.
Cov qauv siv lead ua tau txiav txim siab siv lub cuab yeej XRD (SmartLab SE—HyPix-400) thiab qhov muaj NH4+ cov tshuaj sib xyaw tau raug kuaj pom. Kev piav qhia SEM (Apreo 2 HiVac) tau ua los tshuaj xyuas cov qauv siv lead ua. Cov khoom siv thermal ntawm cov siv lead ua tau txiav txim siab siv lub cuab yeej TGA (TG-209-F1 Libra). Cov pab pawg ua haujlwm tau tshuaj xyuas los ntawm FTIR (JASCO-FT/IR-4X). Qhov huv ntawm cov qauv tau txiav txim siab siv lub cuab yeej ICP-MS (Prodigy DC Arc). Cov qauv tau npaj los ntawm kev yaj 0.5 g ntawm cov siv lead ua hauv 100 mL dej distilled. Qhov crystallization yield (x) tau suav los ntawm kev faib qhov hnyav ntawm cov siv lead ua tso zis los ntawm qhov hnyav ntawm cov siv lead ua nkag raws li cov mis (1).
qhov twg x yog cov zis siv lead ua, hloov pauv ntawm 0 txog 1, mout yog qhov hnyav ntawm cov zis siv lead ua (g), min yog qhov hnyav ntawm cov nkag siv lead ua (g), msol yog qhov hnyav ntawm cov siv lead ua hauv cov kua, thiab mseed yog qhov hnyav ntawm cov noob siv lead ua.
Cov txiaj ntsig ntawm crystallization tau raug tshawb nrhiav ntxiv los txiav txim siab qhov kev loj hlob ntawm crystal kinetics thiab kwv yees qhov txiaj ntsig ntawm lub zog ua kom muaj zog. Kev tshawb fawb no tau ua tiav nrog qhov sib piv ntawm 2% thiab cov txheej txheem sim tib yam li ua ntej. Cov txheej txheem crystallization isothermal tau txiav txim siab los ntawm kev ntsuam xyuas cov txiaj ntsig ntawm crystal ntawm lub sijhawm crystallization sib txawv (10, 20, 30, thiab 40 feeb) thiab qhov kub pib (25, 30, 35, thiab 40 ° C). Cov kev xaiv xaiv ntawm qhov kub pib sib raug rau cov nqi supersaturation (S) ntawm 1.109, 1.052, 1, thiab 0.953, feem. Tus nqi supersaturation tau txiav txim siab los ntawm kev sib piv qhov solubility ntawm cov siv lead ua nickel sulfate yaj nrog qhov solubility ntawm nickel sulfate hexahydrate ntawm qhov kub pib. Hauv kev tshawb fawb no, qhov solubility ntawm NiSO4 6H2O hauv 200 mL dej ntawm qhov kub sib txawv yam tsis muaj impurities tau qhia hauv Daim Duab 2.
Johnson-Mail-Avrami (JMA txoj kev xav) yog siv los tshuaj xyuas tus cwj pwm ntawm isothermal crystallization. JMA txoj kev xav yog xaiv vim tias cov txheej txheem crystallization tsis tshwm sim kom txog thaum cov noob crystals raug ntxiv rau hauv cov tshuaj. JMA txoj kev xav tau piav qhia raws li hauv qab no:
Qhov twg x(t) sawv cev rau qhov kev hloov pauv ntawm lub sijhawm t, k sawv cev rau qhov kev hloov pauv tas mus li, t sawv cev rau lub sijhawm hloov pauv, thiab n sawv cev rau Avrami index. Cov mis 3 yog muab los ntawm cov mis (2). Lub zog ua kom muaj zog ntawm crystallization yog txiav txim siab siv Arrhenius equation:
Qhov twg kg yog qhov nqi ntawm cov tshuaj tiv thaiv tas li, k0 yog qhov tas li, Eg yog lub zog ua kom muaj zog ntawm kev loj hlob ntawm cov siv lead ua, R yog cov roj molar tas li (R = 8.314 J / mol K), thiab T yog qhov kub thiab txias ntawm cov siv lead ua isothermal (K).
Daim Duab 3a qhia tau hais tias qhov piv ntawm kev cog noob thiab qhov concentration ntawm dopant muaj feem cuam tshuam rau qhov tsim tau ntawm cov siv lead ua nickel. Thaum qhov concentration ntawm dopant hauv cov tshuaj nce mus txog 2.5 g/L, qhov tsim tau ntawm cov siv lead ua txo qis los ntawm 7.77% mus rau 6.48% (qhov piv ntawm noob ntawm 0.5%) thiab los ntawm 10.89% mus rau 10.32% (qhov piv ntawm noob ntawm 2%). Kev nce ntxiv ntawm qhov concentration ntawm dopant ua rau qhov tsim tau ntawm cov siv lead ua nce ntxiv. Qhov tsim tau siab tshaj plaws tau txog 17.98% thaum qhov piv ntawm kev cog noob yog 2% thiab qhov concentration ntawm dopant yog 5 g/L. Cov kev hloov pauv ntawm cov qauv tsim tau ntawm cov siv lead ua nrog rau qhov nce ntawm qhov concentration ntawm dopant tej zaum yuav muaj feem cuam tshuam nrog cov kev hloov pauv ntawm cov txheej txheem loj hlob ntawm cov siv lead ua. Thaum qhov concentration ntawm dopant qis, Ni2+ thiab NH4+ ions sib tw rau kev khi nrog SO42−, uas ua rau qhov nce ntawm qhov solubility ntawm nickel hauv cov tshuaj thiab qhov txo qis ntawm qhov tsim tau ntawm cov siv lead ua. 14 Thaum qhov concentration ntawm impurity siab, cov txheej txheem sib tw tseem tshwm sim, tab sis qee cov NH4 + ions sib koom tes nrog nickel thiab sulfate ions los tsim cov ntsev ob npaug ntawm nickel ammonium sulfate. 16 Kev tsim cov ntsev ob npaug ua rau txo qis hauv kev yaj ntawm cov solute, yog li ua rau cov khoom siv lead ua ntau ntxiv. Kev nce qhov piv ntawm kev cog noob tuaj yeem txhim kho cov khoom siv lead ua ntau ntxiv. Cov noob tuaj yeem pib cov txheej txheem nucleation thiab kev loj hlob ntawm cov siv lead ua los ntawm kev muab thaj chaw pib rau cov solute ions los teeb tsa thiab tsim cov siv lead ua. Raws li qhov piv ntawm kev cog noob nce, thaj chaw pib rau cov ions los teeb tsa nce, yog li ntau cov siv lead ua tuaj yeem tsim tau. Yog li ntawd, kev nce qhov piv ntawm kev cog noob muaj qhov cuam tshuam ncaj qha rau qhov kev loj hlob ntawm cov siv lead ua thiab cov khoom siv lead ua. 17
Cov kev ntsuas ntawm NiSO4 6H2O: (a) cov khoom siv lead ua thiab (b) pH ntawm cov kua nickel ua ntej thiab tom qab txhaj tshuaj.
Daim Duab 3b qhia tau hais tias qhov piv ntawm noob thiab qhov concentration ntawm dopant cuam tshuam rau pH ntawm cov kua nickel ua ntej thiab tom qab ntxiv noob. Lub hom phiaj ntawm kev saib xyuas pH ntawm cov kua yog kom nkag siab txog kev hloov pauv ntawm cov tshuaj sib npaug hauv cov kua. Ua ntej ntxiv cov noob siv lead ua, pH ntawm cov kua feem ntau yuav txo qis vim muaj NH4+ ions uas tso H+ protons. Kev nce qhov concentration ntawm dopant ua rau muaj ntau H+ protons raug tso tawm, yog li txo qhov pH ntawm cov kua. Tom qab ntxiv cov noob siv lead ua, pH ntawm txhua cov kua nce ntxiv. Qhov sib txawv pH muaj feem cuam tshuam zoo nrog qhov sib txawv ntawm cov siv lead ua. Tus nqi pH qis tshaj plaws tau txais ntawm qhov concentration ntawm dopant ntawm 2.5 g/L thiab qhov piv ntawm noob ntawm 0.5%. Thaum qhov concentration ntawm dopant nce mus txog 5 g/L, pH ntawm cov kua nce ntxiv. Qhov xwm txheej no nkag siab zoo, vim tias qhov muaj NH4+ ions hauv cov kua txo qis vim yog kev nqus, lossis vim yog kev suav nrog, lossis vim yog kev nqus thiab kev suav nrog ntawm NH4+ ions los ntawm cov siv lead ua.
Cov kev sim thiab kev tshuaj xyuas cov khoom siv lead ua tau ua ntxiv los txiav txim siab txog tus cwj pwm kinetic ntawm kev loj hlob ntawm cov siv lead ua thiab xam lub zog ua haujlwm ntawm kev loj hlob ntawm cov siv lead ua. Cov kev ntsuas ntawm isothermal crystallization kinetics tau piav qhia hauv ntu Txoj Kev. Daim duab 4 qhia txog Johnson-Mehl-Avrami (JMA) daim phiaj uas qhia txog tus cwj pwm kinetic ntawm nickel sulfate crystal loj hlob. Daim phiaj tau tsim los ntawm kev kos tus nqi ln[- ln(1− x(t))] tawm tsam tus nqi ln t (Equation 3). Cov nqi gradient tau los ntawm daim phiaj sib raug rau JMA index (n) tus nqi uas qhia txog qhov ntev ntawm cov siv lead ua loj hlob thiab cov txheej txheem loj hlob. Thaum tus nqi cutoff qhia txog tus nqi loj hlob uas sawv cev los ntawm qhov tas li ln k. Cov nqi JMA index (n) ntau ntawm 0.35 txog 0.75. Tus nqi n no qhia tau tias cov siv lead ua muaj ib-seem kev loj hlob thiab ua raws li cov txheej txheem loj hlob tswj kev sib kis; 0 < n < 1 qhia txog kev loj hlob ib-seem, thaum n < 1 qhia txog cov txheej txheem loj hlob tswj kev sib kis. 18 Qhov kev loj hlob ntawm qhov tsis hloov pauv k txo qis nrog rau qhov kub nce ntxiv, qhia tias cov txheej txheem crystallization tshwm sim sai dua ntawm qhov kub qis dua. Qhov no muaj feem cuam tshuam nrog kev nce ntxiv ntawm supersaturation ntawm cov tshuaj ntawm qhov kub qis dua.
Cov duab ntawm Johnson-Mehl-Avrami (JMA) ntawm nickel sulfate hexahydrate ntawm qhov kub sib txawv ntawm crystallization: (a) 25 °C, (b) 30 °C, (c) 35 °C thiab (d) 40 °C.
Qhov ntxiv cov dopants tau qhia txog tib qho qauv ntawm kev loj hlob ntawm txhua qhov kub thiab txias. Thaum qhov concentration ntawm dopant yog 2.5 g/L, qhov kev loj hlob ntawm cov siv lead ua txo qis, thiab thaum qhov concentration ntawm dopant siab dua 2.5 g/L, qhov kev loj hlob ntawm cov siv lead ua nce ntxiv. Raws li tau hais ua ntej, qhov kev hloov pauv ntawm tus qauv ntawm kev loj hlob ntawm cov siv lead ua yog vim muaj kev hloov pauv ntawm cov txheej txheem ntawm kev sib cuam tshuam ntawm cov ions hauv cov tshuaj. Thaum qhov concentration ntawm dopant qis, cov txheej txheem sib tw ntawm cov ions hauv cov tshuaj ua rau cov solute solubility ntau ntxiv, yog li txo qhov kev loj hlob ntawm cov siv lead ua. 14 Ntxiv mus, qhov kev ntxiv ntawm cov concentration siab ntawm dopants ua rau cov txheej txheem loj hlob hloov pauv ntau heev. Thaum qhov concentration ntawm dopant tshaj 3.75 g/L, cov nuclei siv lead ua tshiab ntxiv tau tsim, uas ua rau qhov kev txo qis ntawm cov solute solubility, yog li ua rau qhov kev loj hlob ntawm cov siv lead ua ntau ntxiv. Kev tsim cov nuclei siv lead ua tshiab tuaj yeem pom los ntawm kev tsim cov ntsev ob npaug (NH4)2Ni(SO4)26H2O. 16 Thaum tham txog txoj kev loj hlob ntawm cov siv lead ua, cov txiaj ntsig ntawm X-ray diffraction lees paub qhov kev tsim ntawm cov ntsev ob npaug.
Lub luag haujlwm JMA plot tau raug soj ntsuam ntxiv kom paub txog lub zog ua kom muaj zog ntawm crystallization. Lub zog ua kom muaj zog tau suav los ntawm kev siv Arrhenius equation (qhia hauv Equation (4)). Daim duab 5a qhia txog kev sib raug zoo ntawm tus nqi ln (kg) thiab tus nqi 1 / T. Tom qab ntawd, lub zog ua kom muaj zog tau suav los ntawm kev siv tus nqi gradient tau los ntawm daim duab. Daim duab 5b qhia txog cov nqi zog ua kom muaj zog ntawm crystallization nyob rau hauv ntau yam impurity concentration. Cov txiaj ntsig qhia tau tias cov kev hloov pauv ntawm qhov impurity concentration cuam tshuam rau lub zog ua kom muaj zog. Lub zog ua kom muaj zog ntawm crystallization ntawm nickel sulfate crystals tsis muaj impurities yog 215.79 kJ / mol. Thaum qhov impurity concentration ncav cuag 2.5 g / L, lub zog ua kom muaj zog nce ntxiv los ntawm 3.99% mus rau 224.42 kJ / mol. Qhov nce ntawm lub zog ua kom muaj zog qhia tau tias lub zog thaiv ntawm cov txheej txheem crystallization nce ntxiv, uas yuav ua rau txo qis ntawm qhov kev loj hlob ntawm crystal thiab cov khoom siv crystal. Thaum qhov impurity concentration ntau dua 2.5 g / L, lub zog ua kom muaj zog ntawm crystallization txo qis heev. Ntawm qhov concentration ntawm impurity ntawm 5 g/l, lub zog ua kom muaj zog yog 205.85 kJ/mol, uas yog 8.27% qis dua lub zog ua kom muaj zog ntawm qhov concentration ntawm impurity ntawm 2.5 g/l. Kev txo qis ntawm lub zog ua kom muaj zog qhia tau tias cov txheej txheem crystallization tau yooj yim, uas ua rau muaj kev nce ntxiv ntawm kev loj hlob ntawm crystal thiab cov khoom siv crystal.
(a) Kev sib phim ntawm daim phiaj xwm ntawm ln (kg) piv rau 1 / T thiab (b) lub zog ua kom muaj zog Eg ntawm crystallization ntawm ntau yam kev tsis huv.
Lub tshuab loj hlob ntawm cov siv lead ua tau raug tshawb nrhiav los ntawm XRD thiab FTIR spectroscopy, thiab cov kinetics loj hlob ntawm cov siv lead ua thiab lub zog ua haujlwm tau raug soj ntsuam. Daim duab 6 qhia txog cov txiaj ntsig XRD. Cov ntaub ntawv no sib xws nrog PDF # 08–0470, uas qhia tias nws yog α-NiSO4 6H2O (silica liab). Cov siv lead ua koom nrog lub kaw lus tetragonal, pawg chaw yog P41212, cov ntsuas ntawm lub cell yog a = b = 6.782 Å, c = 18.28 Å, α = β = γ = 90 °, thiab qhov ntim yog 840.8 Å3. Cov txiaj ntsig no sib xws nrog cov txiaj ntsig uas tau luam tawm los ntawm Manomenova et al. 19 Kev qhia txog NH4 + ions kuj ua rau muaj kev tsim ntawm (NH4)2Ni (SO4)2 6H2O. Cov ntaub ntawv no koom nrog PDF No. 31–0062. Cov siv lead ua ke yog rau lub kaw lus monoclinic, pawg chaw P21 / a, cov qauv ntawm lub cell yog a = 9.186 Å, b = 12.468 Å, c = 6.242 Å, α = γ = 90 °, β = 106.93 °, thiab qhov ntim yog 684 Å3. Cov txiaj ntsig no yog sib xws nrog kev tshawb fawb yav dhau los uas tau tshaj tawm los ntawm Su et al.20.
Cov qauv X-ray diffraction ntawm cov siv lead ua nickel sulfate: (a–b) 0.5%, (c–d) 1%, (e–f) 1.5%, thiab (g–h) 2% noob piv. Daim duab sab xis yog daim duab loj dua ntawm daim duab sab laug.
Raws li pom hauv Daim Duab 6b, d, f thiab h, 2.5 g/L yog qhov txwv siab tshaj plaws ntawm ammonium concentration hauv cov kua tsis tsim cov ntsev ntxiv. Thaum qhov impurity concentration yog 3.75 thiab 5 g/L, NH4+ ions raug koom ua ke rau hauv cov qauv siv lead ua los tsim cov ntsev sib xyaw (NH4)2Ni(SO4)2 6H2O. Raws li cov ntaub ntawv, qhov siab tshaj plaws ntawm cov ntsev sib xyaw nce ntxiv thaum qhov impurity concentration nce ntxiv ntawm 3.75 mus rau 5 g/L, tshwj xeeb tshaj yog ntawm 2θ 16.47° thiab 17.44°. Qhov nce ntawm qhov siab tshaj plaws ntawm cov ntsev sib xyaw tsuas yog vim lub hauv paus ntsiab lus ntawm kev sib npaug ntawm tshuaj lom neeg. Txawm li cas los xij, qee qhov tsis zoo li qub tau pom ntawm 2θ 16.47°, uas tuaj yeem yog vim qhov elastic deformation ntawm cov siv lead ua. 21 Cov txiaj ntsig ntawm kev piav qhia kuj qhia tau tias qhov sib piv ntawm kev cog noob siab dua ua rau qhov txo qis ntawm qhov siab tshaj plaws ntawm cov ntsev sib xyaw. Qhov piv ntawm noob siab dua ua rau cov txheej txheem crystallization sai dua, uas ua rau cov solute txo qis. Hauv qhov no, cov txheej txheem loj hlob ntawm crystallization yog tsom mus rau noob, thiab kev tsim cov theem tshiab raug cuam tshuam los ntawm qhov txo qis ntawm cov kua. Hauv kev sib piv, thaum qhov piv ntawm noob qis, cov txheej txheem crystallization qeeb, thiab qhov supersaturation ntawm cov kua tseem nyob ntawm qib siab dua. Qhov xwm txheej no ua rau muaj feem ntau ntawm nucleation ntawm cov ntsev ob npaug uas tsis yaj (NH4)2Ni(SO4)2 6H2O. Cov ntaub ntawv siab tshaj plaws rau cov ntsev ob npaug tau muab rau hauv Rooj 3.
Kev piav qhia FTIR tau ua los tshawb xyuas txhua yam kev tsis sib haum xeeb lossis kev hloov pauv ntawm cov qauv hauv lub lattice ntawm tus tswv tsev vim muaj NH4+ ions. Cov qauv nrog qhov sib piv ntawm 2% tau piav qhia. Daim duab 7 qhia txog cov txiaj ntsig ntawm FTIR. Cov ncov dav dav uas pom ntawm 3444, 3257 thiab 1647 cm−1 yog vim yog O-H stretching hom ntawm cov molecules. Cov ncov ntawm 2370 thiab 2078 cm−1 sawv cev rau cov hydrogen bonds intermolecular ntawm cov dej molecules. Cov kab ntawm 412 cm−1 yog vim Ni-O stretching vibrations. Tsis tas li ntawd, cov SO4− ions dawb qhia plaub hom kev co loj ntawm 450 (υ2), 630 (υ4), 986 (υ1) thiab 1143 thiab 1100 cm−1 (υ3). Cov cim υ1-υ4 sawv cev rau cov khoom ntawm cov hom kev co, qhov twg υ1 sawv cev rau hom tsis-degenerate (symmetric stretching), υ2 sawv cev rau hom ob zaug degenerate (symmetric bending), thiab υ3 thiab υ4 sawv cev rau hom triply degenerate (asymmetric stretching thiab asymmetric bending, feem). 22,23,24 Cov txiaj ntsig ntawm kev piav qhia qhia tau hais tias qhov muaj cov ammonium impurities muab ib lub ncov ntxiv ntawm tus lej nthwv dej ntawm 1143 cm-1 (cim nrog lub voj voog liab hauv daim duab). Lub ncov ntxiv ntawm 1143 cm-1 qhia tau hais tias qhov muaj NH4+ ions, tsis hais qhov concentration, ua rau muaj kev cuam tshuam ntawm cov qauv lattice, uas ua rau muaj kev hloov pauv hauv qhov zaus co ntawm cov sulfate ion molecules hauv cov siv lead ua.
Raws li cov txiaj ntsig XRD thiab FTIR cuam tshuam txog tus cwj pwm kinetic ntawm kev loj hlob ntawm crystal thiab lub zog ua kom muaj zog, Daim Duab 8 qhia txog daim duab qhia txog cov txheej txheem crystallization ntawm nickel sulfate hexahydrate nrog rau kev ntxiv NH4+ impurities. Yog tsis muaj impurities, Ni2+ ions yuav tshuaj nrog H2O los tsim nickel hydrate [Ni(6H2O)]2−. Tom qab ntawd, nickel hydrate sib xyaw nrog SO42− ions los tsim Ni(SO4)2 6H2O nuclei thiab loj hlob mus rau hauv nickel sulfate hexahydrate crystals. Thaum muaj qhov concentration qis dua ntawm ammonium impurities (2.5 g/L lossis tsawg dua) ntxiv rau hauv cov tshuaj, [Ni(6H2O)]2− nyuaj rau sib xyaw nrog SO42− ions vim tias [Ni(6H2O)]2− thiab NH4+ ions sib tw rau kev sib xyaw nrog SO42− ions, txawm hais tias tseem muaj cov sulfate ions txaus los tshuaj nrog ob qho tib si ions. Qhov xwm txheej no ua rau muaj kev nce ntxiv ntawm lub zog ua kom muaj zog ntawm crystallization thiab qeeb hauv kev loj hlob ntawm crystal. 14,25 Tom qab cov nickel sulfate hexahydrate nuclei tau tsim thiab loj hlob mus ua cov siv lead ua, ntau NH4+ thiab (NH4)2SO4 ions raug adsorbed rau ntawm qhov chaw siv lead ua. Qhov no piav qhia vim li cas pawg ua haujlwm ntawm SO4− ion (wavenumber 1143 cm−1) hauv NSH-8 thiab NSH-12 cov qauv tseem tsim tsis muaj txheej txheem doping. Thaum qhov concentration ntawm impurity siab, NH4+ ions pib koom ua ke rau hauv cov qauv siv lead ua, tsim cov ntsev ob npaug. 16 Qhov xwm txheej no tshwm sim vim tsis muaj SO42− ions hauv cov tshuaj, thiab SO42− ions khi rau nickel hydrates sai dua li ammonium ions. Lub tshuab no txhawb nqa nucleation thiab kev loj hlob ntawm cov ntsev ob npaug. Thaum lub sijhawm alloying, Ni(SO4)2 6H2O thiab (NH4)2Ni(SO4)2 6H2O nuclei tau tsim tib lub sijhawm, uas ua rau muaj kev nce ntxiv ntawm cov nuclei tau txais. Kev nce ntxiv ntawm cov nuclei txhawb nqa kev nrawm ntawm kev loj hlob ntawm siv lead ua thiab txo qis ntawm lub zog ua kom muaj zog.
Cov tshuaj lom neeg ntawm kev yaj nickel sulfate hexahydrate hauv dej, ntxiv me me thiab ntau ammonium sulfate, thiab tom qab ntawd ua tiav cov txheej txheem crystallization tuaj yeem qhia raws li hauv qab no:
Cov txiaj ntsig ntawm kev piav qhia txog SEM tau qhia nyob rau hauv Daim Duab 9. Cov txiaj ntsig ntawm kev piav qhia qhia tias qhov ntau ntawm cov ntsev ammonium ntxiv thiab qhov piv ntawm kev cog noob tsis cuam tshuam rau cov duab siv lead ua. Qhov loj ntawm cov siv lead ua uas tsim tau tseem nyob ruaj khov, txawm hais tias cov siv lead ua loj dua tshwm sim ntawm qee qhov chaw. Txawm li cas los xij, tseem xav tau kev piav qhia ntxiv kom txiav txim siab qhov cuam tshuam ntawm cov ntsev ammonium thiab qhov piv ntawm kev cog noob rau qhov nruab nrab ntawm cov siv lead ua uas tsim tau.
Cov qauv siv lead ua ntawm NiSO4 6H2O: (a–e) 0.5%, (f–j) 1%, (h–o) 1.5% thiab (p–u) 2% piv ntawm cov noob qhia txog kev hloov pauv ntawm NH4+ concentration los ntawm sab saud mus rau hauv qab, uas yog 0, 1.25, 2.5, 3.75 thiab 5 g/L, raws li.
Daim Duab 10a qhia cov kab TGA ntawm cov siv lead ua uas muaj cov khoom tsis huv sib txawv. Kev tshuaj xyuas TGA tau ua rau cov qauv nrog qhov sib piv ntawm 2%. Kev tshuaj xyuas XRD kuj tau ua rau cov qauv NSH-20 los txiav txim siab cov tshuaj sib xyaw ua ke. Cov txiaj ntsig XRD tau pom hauv Daim Duab 10b lees paub qhov kev hloov pauv hauv cov qauv siv lead ua. Kev ntsuas thermogravimetric qhia tau tias tag nrho cov siv lead ua synthesized qhia txog kev ruaj khov thermal txog li 80 ° C. Tom qab ntawd, qhov hnyav ntawm siv lead ua txo qis 35% thaum qhov kub nce mus txog 200 ° C. Qhov hnyav poob ntawm cov siv lead ua yog vim cov txheej txheem decomposition, uas cuam tshuam nrog kev poob ntawm 5 lub molecule dej los ua NiSO4 H2O. Thaum qhov kub nce mus txog 300–400 ° C, qhov hnyav ntawm cov siv lead ua txo qis dua. Qhov hnyav poob ntawm cov siv lead ua yog li 6.5%, thaum qhov hnyav poob ntawm cov qauv siv lead ua NSH-20 siab dua me ntsis, raws nraim 6.65%. Qhov kev rhuav tshem ntawm NH4+ ions mus ua NH3 roj hauv cov qauv NSH-20 ua rau muaj kev txo qis me ntsis. Thaum qhov kub nce ntxiv ntawm 300 txog 400°C, qhov hnyav ntawm cov siv lead ua tau txo qis, ua rau txhua cov siv lead ua muaj cov qauv NiSO4. Kev nce qhov kub ntawm 700°C txog 800°C ua rau cov qauv siv lead ua hloov mus ua NiO, ua rau muaj cov pa roj SO2 thiab O2 tso tawm.25,26
Qhov purity ntawm nickel sulfate hexahydrate crystals tau txiav txim siab los ntawm kev ntsuas qhov NH4 + concentration siv DC-Arc ICP-MS instrument. Qhov purity ntawm nickel sulfate crystals tau txiav txim siab siv cov mis (5).
Qhov twg Ma yog qhov hnyav ntawm cov khoom tsis huv hauv cov siv lead ua (mg), Mo yog qhov hnyav ntawm cov siv lead ua (mg), Ca yog qhov concentration ntawm cov khoom tsis huv hauv cov tshuaj (mg/l), V yog qhov ntim ntawm cov tshuaj (l).
Daim Duab 11 qhia txog qhov huv ntawm cov siv lead ua los ntawm nickel sulfate hexahydrate. Tus nqi huv yog tus nqi nruab nrab ntawm 3 yam ntxwv. Cov txiaj ntsig qhia tau hais tias qhov piv ntawm kev cog noob thiab qhov concentration ntawm cov khoom tsis huv cuam tshuam ncaj qha rau qhov huv ntawm cov siv lead ua los ntawm nickel sulfate. Qhov siab dua qhov concentration ntawm cov khoom tsis huv, qhov ntau dua qhov nqus ntawm cov khoom tsis huv, ua rau qhov huv qis dua ntawm cov siv lead ua los ntawm. Txawm li cas los xij, tus qauv nqus ntawm cov khoom tsis huv yuav hloov pauv nyob ntawm qhov concentration ntawm cov khoom tsis huv, thiab daim duab qhia tau hais tias qhov kev nqus tag nrho ntawm cov khoom tsis huv los ntawm cov siv lead ua tsis hloov pauv ntau. Tsis tas li ntawd, cov txiaj ntsig no kuj qhia tau hais tias qhov piv ntawm kev cog noob siab dua tuaj yeem txhim kho qhov huv ntawm cov siv lead ua. Qhov xwm txheej no ua tau vim tias thaum feem ntau ntawm cov nuclei siv lead ua uas tsim tau raug tsom mus rau ntawm cov nuclei nickel, qhov muaj feem ntawm cov ions nickel sib sau ua ke ntawm nickel yog siab dua. 27
Txoj kev tshawb fawb qhia tau hais tias ammonium ions (NH4 +) cuam tshuam rau cov txheej txheem crystallization thiab cov khoom siv crystalline ntawm nickel sulfate hexahydrate crystals, thiab kuj tau qhia txog kev cuam tshuam ntawm cov noob piv rau cov txheej txheem crystallization.
Thaum muaj ammonium concentration siab tshaj 2.5 g/l, qhov ua tau ntawm cov siv lead ua thiab qhov nrawm ntawm kev loj hlob ntawm cov siv lead ua yuav txo qis. Thaum muaj ammonium concentration siab tshaj 2.5 g/l, qhov ua tau ntawm cov siv lead ua thiab qhov nrawm ntawm kev loj hlob ntawm cov siv lead ua yuav nce ntxiv.
Ntxiv cov khoom tsis huv rau hauv cov kua nickel ua rau muaj kev sib tw ntawm NH4+ thiab [Ni(6H2O)]2− ions rau SO42−, uas ua rau muaj kev nce ntxiv ntawm lub zog ua kom muaj zog. Qhov txo qis ntawm lub zog ua kom muaj zog tom qab ntxiv cov khoom tsis huv ntau yog vim NH4+ ions nkag mus rau hauv cov qauv siv lead ua, yog li tsim cov ntsev ob npaug (NH4)2Ni(SO4)2 6H2O.
Siv cov piv txwv cog qoob loo siab dua tuaj yeem txhim kho cov qoob loo siv lead ua, kev loj hlob ntawm cov siv lead ua thiab kev ntshiab ntawm cov siv lead ua ntawm nickel sulfate hexahydrate.
Demirel, HS, thiab lwm tus. Kev siv cov tshuaj tua kab mob ntawm cov roj teeb-qib nickel sulfate hydrate thaum lub sijhawm ua laterite. Cuaj Hlis. Purification Technology, 286, 120473. https://doi.org/10.1016/J.SEPPUR.2022.120473 (2022).
Saguntala, P. thiab Yasota, P. Kev siv optical ntawm nickel sulfate crystals ntawm qhov kub siab: Kev tshawb fawb txog tus cwj pwm nrog ntxiv cov amino acids ua dopants. Mater. Niaj hnub no Proc. 9, 669–673. https://doi.org/10.1016/J.MATPR.2018.10.391 (2019).
Babaahmadi, V., et al. Electrodeposition ntawm cov qauv nickel ntawm cov ntaub ntawv nrog polyol-mediated luam ntawv ntawm graphene oxide txo qis. Phau ntawv Journal of Physical and Chemical Engineering of Colloidal Surfaces 703, 135203. https://doi.org/10.1016/J.COLSURFA.2024.135203 (2024).
Fraser, J., Anderson, J., Lazuen, J., et al. "Kev thov thiab kev ruaj ntseg ntawm kev muab nickel rau cov roj teeb tsheb fais fab yav tom ntej." Chaw Haujlwm Luam Tawm ntawm European Union; (2021). https://doi.org/10.2760/212807
Hahn, B., Böckman, O., Wilson, BP, Lundström, M. thiab Louhi-Kultanen, M. Kev ntxuav nickel sulfate los ntawm kev sib xyaw ua ke nrog kev txias. Kev Siv Tshuaj Lom Zem 42(7), 1475–1480. https://doi.org/10.1002/CEAT.201800695 (2019).
Ma, Y. et al. Kev siv cov txheej txheem nag thiab crystallization hauv kev tsim cov ntsev hlau rau cov khoom siv roj teeb lithium-ion: kev tshuaj xyuas. Hlau. 10 (12), 1-16. https://doi.org/10.3390/MET10121609 (2020).
Masalov, VM, et al. Kev loj hlob ntawm nickel sulfate hexahydrate (α-NiSO4.6H2O) ib leeg siv lead ua nyob rau hauv qhov kub thiab txias gradient mob. Crystallography. 60(6), 963–969. https://doi.org/10.1134/S1063774515060206 (2015).
Choudhury, RR et al. α-Nickel sulfate hexahydrate crystals: Kev sib raug zoo ntawm kev loj hlob, cov qauv siv lead ua, thiab cov khoom. JApCr. 52, 1371–1377. https://doi.org/10.1107/S1600576719013797FILE (2019).
Hahn, B., Böckman, O., Wilson, BP, Lundström, M. thiab Louhi-Kultanen, M. Kev ntxuav nickel sulfate los ntawm kev siv crystallization txias ua ke. Chemical Engineering Technology 42(7), 1475–1480. https://doi.org/10.1002/ceat.201800695 (2019).