46.Yintoni ioksijini enyibilikisiweyo?
I-oksijini enyibilikisiweyo DO (isifinyezo se-Oxygen eNyibilikileyo ngesiNgesi) imele ubungakanani be-oksijini yemolekyuli enyityilikiswe emanzini, kwaye iyunithi ngu-mg/L. Umxholo ogcweleyo we-oksijini enyityilisiweyo emanzini uhambelana nobushushu bamanzi, uxinzelelo lwe-atmospheric kunye nokwakheka kweekhemikhali zamanzi. Ngoxinzelelo olulodwa lwe-atmospheric, umxholo we-oksijeni xa i-oksijeni echithwe emanzini adibeneyo ifikelela kwi-saturation kwi-0oC yi-14.62mg / L, kwaye kwi-20oC yi-9.17mg / L. Ukunyuka kobushushu bamanzi, ukunyuka kwetyuwa, okanye ukuhla koxinzelelo lwe-atmospheric kuya kubangela ukuba umxholo we-oksijini ochithwe emanzini unciphise.
Ioksijini enyibilikisiweyo yinto ebalulekileyo yokuphila kunye nokuveliswa kweentlanzi kunye neebhaktheriya ze-aerobic. Ukuba i-oksijeni echithiweyo ingaphantsi kwe-4mg / L, kuya kuba nzima ukuba intlanzi iphile. Xa amanzi engcoliswe yi-organic matter, i-oxidation ye-organic matter yi-aerobic microorganisms iya kudla i-oksijini enyibilikisiweyo emanzini. Ukuba ayinakuzaliswa emoyeni ngexesha, ioksijini enyibilikisiweyo emanzini iya kuncipha ngokuthe ngcembe de ibe kufutshane ne-0, ibangela ukuba inani elikhulu le-anaerobic microorganisms liphindaphindeke. Yenza amanzi abe mnyama kwaye abe nevumba.
47. Zeziphi iindlela ezisetyenziswa ngokuqhelekileyo zokulinganisa ioksijini enyibilikileyo?
Kukho iindlela ezimbini ezisetyenziswa ngokuqhelekileyo zokulinganisa ioksijini enyibilikisiweyo, enye yindlela ye-iodometric kunye nendlela yokulungiswa kwayo (GB 7489-87), kwaye enye yindlela ye-electrochemical probe method (GB11913-89). Indlela ye-iodometric ilungele ukulinganisa iisampulu zamanzi kunye neoksijini enyibilikileyo enkulu kune-0.2 mg/L. Ngokuqhelekileyo, indlela ye-iodometric ifanelekile kuphela ukulinganisa i-oksijeni echithwe emanzini acocekileyo. Xa ulinganisa ioksijini enyibilikisiweyo kumanzi amdaka emizi-mveliso okanye amanyathelo ahlukeneyo enkqubo yokucocwa kwamanzi amdaka, kufuneka kusetyenziswe i-iodine elungisiweyo. indlela yobungakanani okanye indlela ye-electrochemical. Umda ophantsi wokumisela indlela ye-electrochemical probe ihambelana nesixhobo esisetyenzisiweyo. Kukho iintlobo ezimbini kakhulu: indlela ye-membrane ye-electrode kunye ne-membrane electrode method. Ngokuqhelekileyo zilungele ukulinganisa iisampulu zamanzi kunye neoksijini enyibilikisiweyo enkulu kuno-0.1mg/L. Imitha ye-DO ye-intanethi efakwe kwaye isetyenziswe kwiitanki zokungenisa umoya kunye nezinye iindawo kwiindawo zokucocwa kwamanzi amdaka zisebenzisa indlela ye-membrane ye-electrode okanye i-membrane-less electrode method.
Umgaqo osisiseko wendlela ye-iodometric kukongeza i-manganese sulfate kunye ne-alkaline potassium iodide kwisampuli yamanzi. Ioksijini enyibilikisiweyo emanzini idibanisa i-manganese ephantsi ukuya kwi-high-valent manganese, ivelisa i-brown precipitate ye-tetravalent manganese hydroxide. Emva kokongeza i-asidi, i-brown precipitate iyanyibilika kwaye Isabela kunye ne-iodide ion ukuvelisa iodine yasimahla, kwaye emva koko isebenzisa istatshi njengesalathisi kwaye ibeka i-iodine yasimahla nge-sodium thiosulfate ukubala umxholo weoksijini onyibilikileyo.
Xa isampuli yamanzi inombala okanye iqulethe izinto eziphilayo ezinokusabela nge-iodine, ayifanelekanga ukusebenzisa indlela ye-iodometric kunye nendlela yokulungiswa kwayo ukulinganisa i-oksijeni echithwe emanzini. Endaweni yoko, i-electrode yefilimu ye-oxygen-sensitive film okanye i-membrane-less electrode ingasetyenziselwa ukulinganisa. I-electrode ye-oxygen-sensitive electrode iqukethe i-electrode ezimbini zetsimbi ezidibanisa ne-electrolyte exhasayo kunye ne-membrane ekhethiweyo ekhethiweyo. I-membrane inokudlula kuphela kwi-oksijeni kunye nezinye iigesi, kodwa amanzi kunye nezinto ezinyibilikayo kuyo azikwazi ukudlula. I-oksijeni edlula kwi-membrane iyancipha kwi-electrode. Ukusasazwa okubuthathaka okwangoku kuveliswa, kwaye ubungakanani bangoku bulingana nomxholo we-oksijeni ochithwe kwiqondo lokushisa elithile. I-electrode engenafilimu iqulunqwe yi-cathode ekhethekileyo yesilivere ye-alloy kunye ne-iron (okanye i-zinc) anode. Ayisebenzisi ifilimu okanye i-electrolyte, kwaye akukho mbane we-polarization wongezwa phakathi kwezibonda ezimbini. Inxibelelana kuphela nezibonda ezimbini ngesisombululo samanzi esilinganisiweyo ukwenza ibhetri ephambili, kwaye iimolekyuli ze-oksijini emanzini ziNciphiso lwenziwa ngokuthe ngqo kwi-cathode, kwaye ukuncipha kwangoku okwenziweyo kuhambelana nomxholo we-oksijini kwisisombululo esilinganiswayo. .
48. Kutheni isalathisi se-oksijini enyibilikisiweyo sesinye sezalathi ezingundoqo zendlela yokusebenza eqhelekileyo yesixokelelwano sebhayoloji yamanzi amdaka?
Ukugcina umlinganiselo othile weoksijini enyibilikisiweyo emanzini yimeko esisiseko yokuphila kunye nokuveliswa kwezinto eziphilayo zasemanzini ze-aerobic. Ngoko ke, isalathisi se-oksijeni echithiweyo sesinye sezibonakaliso eziphambili zendlela yokusebenza eqhelekileyo yenkqubo yokucoca ibhayoloji.
Isixhobo sonyango lwebhayoloji ye-aerobic sifuna ioksijini enyityilisiweyo emanzini ibe ngaphezulu kwe-2 mg/L, kwaye isixhobo sonyango lwebhayoloji ye-anaerobic sifuna ioksijini enyityilisiweyo ibe ngaphantsi kwe-0.5 mg/L. Ukuba ufuna ukungena kwisigaba esifanelekileyo se-methanogenesis, kungcono ukuba ungabikho i-oksijeni edibeneyo (ye-0), kwaye xa icandelo A lenkqubo ye-A / O ikwimeko ye-anoxic, i-oxygen echithwe ngokukhethekileyo i-0.5 ~ 1mg / L. . Xa amanzi amdaka asuka kwitanki yesibini yentlenge yendlela yebhayoloji yebhayoloji efanelekile, isiqulatho sawo seoksijini enyibilikisiweyo asibikho ngaphantsi kwe-1mg/L. Ukuba iphantsi kakhulu (<0.5mg/L) okanye phezulu kakhulu (indlela yokungenisa umoya>2mg/L), iya kubangela ukulahlwa kwamanzi. Umgangatho wamanzi uyehla okanye ude wodlule imigangatho. Ngoko ke, ingqwalasela epheleleyo kufuneka ihlawulwe ekubekeni iliso umxholo we-oksijini echithiweyo ngaphakathi kwesixhobo sonyango lwebhayoloji kunye nokungcola kwetanki yayo ye-sedimentation.
I-titration ye-Iodometric ayifanelekanga ukuvavanywa kwisayithi, kwaye ayinakusetyenziselwa ukubeka iliso ngokuqhubekayo okanye ukuzimisela kwendawo ye-oksijini echithiweyo. Ekubekeni iliso ngokuqhubekayo kwe-oksijini echithwe kwiinkqubo zokucocwa kwamanzi amdaka, indlela ye-membrane ye-electrode kwindlela ye-electrochemical isetyenziswa. Ukuze ubambe ngokuqhubekayo utshintsho kwi-DO yolwelo oluxubeneyo kwitanki yokufaka umoya ngexesha lenkqubo yokucoca ugutyulo ngexesha lokwenyani, kusetyenziswa imitha ye-DO ye-electrochemical probe ngokubanzi. Ngelo xesha, imitha ye-DO nayo iyinxalenye ebalulekileyo yolawulo oluzenzekelayo kunye nenkqubo yokulungelelanisa ye-oksijini echithwe kwi-tank ye-aeration. Kuba inkqubo yohlengahlengiso kunye nokulawula idlala indima ebalulekileyo ekusebenzeni kwayo okuqhelekileyo. Ngexesha elifanayo, kwakhona isiseko esibalulekileyo kubaqhubi benkqubo ukulungelelanisa nokulawula ukusebenza okuqhelekileyo kwonyango lwebhayoloji yogutyulo.
49. Zeziphi izilumkiso zokulinganisa ioksijini enyibilikileyo nge-iodometric titration?
Unonophelo olukhethekileyo kufuneka luthathwe xa kuqokelela iisampulu zamanzi zokulinganisa i-oksijini echithiweyo. Iisampuli zamanzi akufanele zidibane nomoya ixesha elide kwaye akufanele zishukunyiswe. Xa uthatha iisampulu kwitanki yokuqokelela amanzi, sebenzisa ibhotile yeoksijini enyityilisiweyo yeglasi engama-300 ml, kwaye ulinganise kwaye urekhode ubushushu bamanzi ngaxeshanye. Ngaphezu koko, xa usebenzisa i-iodometric titration, ngaphezu kokukhetha indlela ethile yokuphelisa ukuphazamiseka emva kwesampuli, ixesha lokugcina kufuneka lifinyezwe kangangoko kunokwenzeka, kwaye kungcono ukuhlalutya ngokukhawuleza.
Ngokuphuculwa kwethekhnoloji kunye nezixhobo kunye ngoncedo lwezixhobo, i-iodometric titration ihlala iyona ndlela ichanekileyo kwaye inokwethenjelwa ye-titration yohlalutyo lwe-oxygen echithwe. Ukuze kupheliswe impembelelo yezinto ezahlukeneyo eziphazamisayo kwiisampuli zamanzi, kukho iindlela ezininzi zokulungiswa kwe-iodometric titration.
I-oxides, i-reductants, i-organic matter, njl njl. ekhoyo kwiisampuli zamanzi iya kuphazamisa i-iodometric titration. Ezinye ii-oxidants zinokuhlukanisa i-iodide ibe yi-iodine (ukuphazamiseka okulungileyo), kwaye ezinye ii-agent zokunciphisa zinokunciphisa i-iodine kwi-iodide (ukuphazamiseka okubi). Ukuphazamiseka), xa i-oxidized manganese precipitate i-acidified, i-organic matter inokuthi ifakwe i-oxidized ngokuyinxenye, ivelise iimpazamo ezimbi. Indlela yokulungiswa kwe-azide inokuphelisa ngokufanelekileyo ukuphazamiseka kwe-nitrite, kwaye xa isampuli yamanzi iqulethe isinyithi esiphantsi, indlela yokulungiswa kwe-potassium permanganate ingasetyenziselwa ukuphelisa ukuphazamiseka. Xa isampuli yamanzi iqulethe umbala, i-algae, kunye nezinto eziqinileyo ezimisiweyo, indlela yokulungiswa kwe-alum flocculation kufuneka isetyenziswe, kwaye indlela yokulungiswa kwe-copper sulfate-sulfamic acid flocculation isetyenziselwa ukumisela i-oksijini enyibilikileyo yomxube we-sludge osebenzayo.
50. Ngawaphi amanyathelo okuthintela ukulinganisa ioksijini enyibilikisiweyo kusetyenziswa indlela yefilimu ebhityileyo ye-electrode?
I-electrode ye-membrane iqukethe i-cathode, i-anode, i-electrolyte kunye ne-membrane. I-electrode cavity igcwele isisombululo se-KCl. I-membrane ihlukanisa i-electrolyte kwisampuli yamanzi ukuze ilinganiswe, kwaye i-oksijini echithwayo ingena kwaye isasazeke kwi-membrane. Emva kokuba i-DC esisigxina ye-polarization voltage ye-0.5 ukuya kwi-1.0V isetyenziswe phakathi kwezibonda ezimbini, i-oksijini echithwe kumanzi alinganisiweyo idlula kwifilimu kwaye iyancipha kwi-cathode, ivelise i-diffusion yangoku ngokulinganayo kwi-concentration ye-oksijeni.
Iifilimu ezisetyenziswa ngokuqhelekileyo ziyi-polyethylene kunye neefilimu ze-fluorocarbon ezinokuvumela iimolekyuli ze-oksijini ukuba zidlule kwaye zibe neepropati ezizinzileyo. Ngenxa yokuba ifilimu inokungena kwiindidi zegesi, ezinye iigesi (ezifana ne-H2S, SO2, CO2, NH3, njl.) zikwi-electrode ebonisayo. Akulula ukuba i-depolarize, eya kunciphisa uvakalelo lwe-electrode kwaye iholele ekuphambukeni kwiziphumo zokulinganisa. I-oyile kunye negrisi kumanzi alinganisiweyo kunye ne-microorganisms kwi-tank ye-aeration zihlala zibambelela kwi-membrane, zichaphazela kakhulu ukuchaneka komlinganiselo, ngoko ke ukucoca rhoqo kunye nokulinganisa kuyadingeka.
Ngoko ke, i-membrane ye-electrode echithwayo i-oxygen analyzers esetyenziswa kwiinkqubo zokunyanga kwamanzi amdaka kufuneka iqhutywe ngokungqongqo ngokuhambelana neendlela zokulinganisa zomenzi, kunye nokucoca rhoqo, ukulinganisa, ukubuyisela i-electrolyte, kunye nokutshintshwa kwe-membrane ye-electrode. Xa utshintsha ifilimu, kufuneka uyenze ngononophelo. Okokuqala, kufuneka uthintele ukungcoliseka kwamalungu abuthathaka. Okwesibini, qaphela ukuba ungashiyi amaqamza amancinci phantsi kwefilimu. Ngaphandle koko, i-residual current iya kwanda kwaye ichaphazele iziphumo zokulinganisa. Ukuze kuqinisekiswe idatha echanekileyo, ukuhamba kwamanzi kwindawo yokulinganisa i-membrane ye-electrode kufuneka ibe neqondo elithile le-turbulence, oko kukuthi, isisombululo sokuvavanya esidlula kwi-membrane surface kufuneka sibe nesantya esaneleyo sokuhamba.
Ngokubanzi, umoya okanye iisampulu ezinezigxina ze-DO ezaziwayo kunye neesampuli ngaphandle kwe-DO zingasetyenziselwa ukulawula ukulinganisa. Ngokuqinisekileyo, kungcono ukusebenzisa isampuli yamanzi phantsi kokuhlolwa kokulinganisa. Ukongezelela, inqaku elinye okanye ezimbini kufuneka zihlolwe rhoqo ukuze kuqinisekiswe idatha yokulungiswa kweqondo lokushisa.
Ixesha lokuposa: Nov-14-2023
