I-Dioxane？ Yinto nje yokucalucalula
Yintoni i-dioxane? Ivela phi?
I-Dioxane, indlela echanekileyo yokuyibhala yi-dioxane. Ngenxa yokuba ububi kunzima kakhulu ukububhala, kweli nqaku siza kusebenzisa amagama amabi aqhelekileyo endaweni yoko. Yikhompawundi yendalo, eyaziwa ngokuba yi-dioxane, i-1, i-4-dioxane, ulwelo olungenambala. I-Dioxane acute toxicity yityhefu ephantsi, ine-anesthetic kunye neziphumo ezivuselelayo. NgokweKhowudi yoBugcisa boKhuseleko yangoku eTshayina, i-dioxane yinxalenye engavumelekanga yezithambiso. Ekubeni kungavumelekanga ukongeza, kutheni izithambiso zisenokufunyanwa yi-dioxane? Ngezizathu ezingenakuphepheka ngokwetekhnoloji, kunokwenzeka ukuba i-dioxane ifakwe kwizithambiso njengokungcola. Ngoko ke zeziphi izinto ezingcolileyo kwizixhobo eziluhlaza?
Esinye sezithako zokucoca ezisetyenziswa kakhulu kwiishampu kunye nokuhlamba umzimba yi-sodium fatty alcohol ether sulfate, eyaziwa ngokuba yi-sodium AES okanye i-SLES. Eli candelo linokwenziwa ngeoyile yesundu yendalo okanye ipetroleum njengezinto eziluhlaza zibe yi-fatty alcohols, kodwa lenziwa ngothotho lwamanyathelo afana ne-ethoxylation, i-sulfonation, kunye ne-neutralization. Inyathelo eliphambili yi-ethoxylation, kweli nyathelo lenkqubo yokusabela, kufuneka usebenzise izinto eziluhlaza ze-ethylene oxide, eyi-monomer yezinto eziluhlaza esetyenziswa kakhulu kushishino lokwenziwa kweekhemikhali, kwinkqubo yokusabela kwe-ethoxylation, ukongeza kokongeza i-ethylene oxide kwi-fatty alcohol ukuvelisa i-ethoxylated fatty alcohol. Kukwakho nenxalenye encinci ye-ethylene oxide (EO) iimolekyuli ezimbini ezimbini zokudibanisa ukuvelisa imveliso engasemva, oko kukuthi, utshaba lwe-dioxane, impendulo ethile ingaboniswa kumfanekiso olandelayo:
Ngokubanzi, abavelisi bezinto eziluhlaza baya kuba namanyathelo alandelayo okwahlula nokucoca i-dioxane, abavelisi bezinto eziluhlaza ezahlukeneyo baya kuba nemigangatho eyahlukileyo, abavelisi bezinto zokuthambisa bamazwe ngamazwe baya kulawula esi salathisi, ngokubanzi malunga ne-20 ukuya kwi-40ppm. Ngokuphathelele umgangatho womxholo kwimveliso egqityiweyo (njengeshampu, ukuhlamba umzimba), akukho zibonakaliso ezithile zamazwe ngamazwe. Emva kwesiganeko seshampu saseBawang ngo-2011, iTshayina yabeka umgangatho weemveliso ezigqityiweyo ngaphantsi kwe-30ppm.
I-Dioxane ibangela umhlaza, ngaba ibangela iingxaki zokhuseleko?
Njengezinto ezisetyenzisiweyo ukususela kwiMfazwe Yehlabathi yesiBini, i-sodium sulfate (SLES) kunye ne-dioxane ephuma kwimveliso yayo ziye zafundwa ngokubanzi. I-United States Food and Drug Administration (FDA) ibisoloko ifunda i-dioxane kwiimveliso zabathengi kangangeminyaka engama-30, kwaye i-Health Canada igqibe kwelokuba ukubakho kwezixa ezimbalwa ze-dioxane kwiimveliso zezithambiso akubeki mngcipheko kwimpilo yabathengi, kwanabantwana (eKhanada). Ngokutsho kwe-Australian National Occupational Health and Safety Commission, umda ofanelekileyo we-dioxane kwiimpahla zabathengi yi-30ppm, kwaye umda ophezulu owamkelekileyo ngokwetyhefu yi-100ppm. E-China, emva kowama-2012, umgangatho omiselweyo we-30ppm womxholo we-dioxane kwiizithambiso ungaphantsi kakhulu kunomda ophezulu owamkelekileyo ngokwetyhefu we-100ppm phantsi kweemeko eziqhelekileyo zokusetyenziswa.
Kwelinye icala, kufuneka kugxininiswe ukuba umda we-dioxane eTshayina kwimigangatho yokuhombisa ungaphantsi kwe-30ppm, nto leyo esemgangathweni ophezulu kwihlabathi liphela. Kuba eneneni, amazwe amaninzi kunye nemimandla inemida ephezulu kumxholo we-dioxane kunemigangatho yethu okanye akukho migangatho icacileyo:
Enyanisweni, ubuninzi be-dioxane buqhelekile kwindalo. I-US Toxic Substances and Disease Registry idwelisa i-dioxane njengefumaneka kwinkukhu, iitumato, ii-shrimp kwanasemanzini ethu okusela. Izikhokelo ze-World Health Organisation for Selling Water Quality (uhlelo lwesithathu) zithi umda we-dioxane emanzini yi-50 μg/L.
Ngoko ke ukushwankathela ingxaki ebangela umhlaza ye-dioxane kwisivakalisi esinye, oko kukuthi: nokuba ingakanani na idosi ukuthetha ngomonakalo kukunganyaniseki.
Okukhona umxholo we-dioxane uphantsi, kokukhona umgangatho ungcono, akunjalo?
I-Dioxane ayilophawu lodwa lomgangatho we-SLES. Ezinye izalathisi ezifana nobungakanani beekhompawundi ezingenasulfona kunye nobungakanani bezinto ezibangela ukucaphuka kwimveliso nazo zibalulekile ukuziqwalasela.
Ukongeza, kubalulekile ukuqaphela ukuba ii-SLES nazo ziza ngobukhulu obahlukeneyo, umahluko omkhulu kukuba zingakanani i-ethoxylation, ezinye zine-1 EO, ezinye zine-2, 3 okanye ne-4 EO (ewe, iimveliso ezineendawo zedesimali ezifana ne-1.3 kunye ne-2.6 nazo zinokuveliswa). Okukhona inqanaba le-ethoxidation eyonyukileyo liphezulu, oko kukuthi, inani le-EO liphezulu, kokukhona umxholo we-dioxane uphezulu phantsi kwenkqubo efanayo kunye neemeko zokucoca.
Okubangel’ umdla kukuba, isizathu sokwandisa i-EO kukunciphisa ukucaphuka kwe-surfactant SLES, kwaye okukhona inani le-EO SLES liphezulu, kokukhona kungacaphukisi ulusu, oko kukuthi, kuthambile, kwaye ngokuchaseneyo. Ngaphandle kwe-EO, yi-SLS, engathandekiyo zizinto eziyinxalenye yayo, eyinto evuselelayo kakhulu.
Ngoko ke, umxholo ophantsi we-dioxane akuthethi ukuba yinto elungileyo ekrwada. Kuba ukuba inani le-EO lincinci, ukucaphuka kwezinto ezikrwada kuya kuba kukhulu.
Isishwankathelo:
I-Dioxane ayisosithako esongezwa ngamashishini, kodwa sisixhobo esiluhlaza esimele sihlale kwizinto eziluhlaza ezifana ne-SLES, nto leyo enzima ukuyiphepha. Ayisiyo kwi-SLES kuphela, enyanisweni, lo gama nje i-ethoxylation isenziwa, kuya kubakho inani elincinci le-dioxane, kwaye ezinye izinto eziluhlaza zokhathalelo lolusu nazo ziqulethe i-dioxane. Ngokwembono yovavanyo lomngcipheko, njengento eseleyo, akukho mfuneko yokulandela umxholo we-0 opheleleyo, thatha itekhnoloji yokufumanisa yangoku, "engafunyanwanga" akuthethi ukuba umxholo ngu-0.
Ngoko ke, ukuthetha ngomonakalo ongaphaya komlinganiselo kukuba ligqwirha. Ukhuseleko lwe-dioxane luye lwafundwa iminyaka emininzi, kwaye ukhuseleko olufanelekileyo kunye nemigangatho ecetyiswayo iye yasekwa, kwaye iintsalela ezingaphantsi kwe-100ppm zithathwa njengezikhuselekileyo. Kodwa amazwe afana ne-European Union awazange ayenze ibe ngumgangatho onyanzelekileyo. Iimfuno zasekhaya zomxholo we-dioxane kwiimveliso zingaphantsi kwe-30ppm.
Ngoko ke, i-dioxane ekwishampu ayidingi kuxhalaba ngomhlaza. Ngokuphathelele ulwazi olungeyonyani oluvela kwiindaba, ngoku uyaqonda ukuba kukufumana nje ingqalelo.