Loại bỏ Asen và Mangan trong nước ngầm bằng quặng Mangan Đioxit và Diatomit tự nhiên

Hgi nghi Khoa hgc ky niem 35 ndm Vien Khoa hgc vd Cong nghe Viet Nam - Hd Noi 10/2010<br /> <br /> <br /> LOAI BO ASEN VA MANGAN TRONG NlT^C NGAM<br /> BANG QUANG MANGAN DIOXIT vA DIATOMIT TlT NHIEN<br /> <br /> Nguyen Thi Hue\ Le Thi Hoai Nam , Biii Duy Cam<br /> Vien Cong nghe Moi trudng; Vien Hoa hgc; 18 - Hoang Quoc Viet, Cau Giay, Ha Noi<br /> •^Trudng Dai hpc Khoa hoc Tu Nhien, DHQGHN<br /> Email: nthue2003@yahoo.com<br /> Tom tat:<br /> Phuang phdp da duac nghien cicu nhdm logi bd Asen vd Mangan trong nude<br /> ngdm khi sic dung manganese dioxide tu nhien vd khodng diatomit tren ca sd hdp<br /> phu. Mdu nude ngdm dupe ldy tgi Idng Vgn Phuc, Thanh Tri, Hd Ndi cd hdm<br /> luang As vd Mn cao han tiiu chudn Viet Nam cho phep nhiiu ldn. Kit qud nghien<br /> ciru cho thdy, khodng 90-96% As vd Mn trong nude ngdm dupe logi bd khi sic<br /> dung vdt lieu hdp phu Mn02 vd diatomit. Sau xic ly, ndng dp As vd Mn thdp han<br /> tiiu chudn cho phep. Mn02 tu nhien vd qudng diatomit cd thi diing de logi bd<br /> tdng As (III, V) md khdng qua qud trinh oxi hda. Sic dung Mn02 vd diatomit vd<br /> ciing hiiu qud di logi bd As vd Mn trong nude ngdm. Logi bd As vd Mn bdng vdt<br /> lieu diatomit tdt han Mn02.<br /> Abstract:<br /> A methodology has been developed for removal of arsenic (As) and manganese<br /> (Mn) from groundwater using natural manganese dioxide (Mn02) and diatomite<br /> mineral based the adsorption. The groundwater, which is collected in Van Phuc<br /> village, Thanh Tri, Hanoi has the concentration of As and Mn higher than the<br /> Vietnamese Standard more than manifold. The results showed that 90 - 96%<br /> concentration of As and/or Mn had removed from groundwater by Mn02 and<br /> diatomite adsorbent materials. After treating, the concentration of As and Mn is<br /> lower than the permitted standard. The natural Mn02 and diatomite mineral are<br /> able to remove a total of As (III, V) without the oxidation reagents. Using the<br /> nature Mn02 and diatomite mineral are extremely efficiency for removing As and<br /> Mn in the groundwater. The remove of As and Mn by using diatomite is more<br /> efficient than the Mn02.<br /> <br /> <br /> 1. MO DAU<br /> Hien nay 6 nhiem Asen (As) trong nude an va nude sinh boat dang la van de quan tam<br /> hang dau cua ca the gidi. Nhiem dgc As se gay ra met moi, roi loan sac to, anb budng den be<br /> than kinh, tham chi gay ung thu da day va mot so co quan noi tang khac [1, 2]. Dli vdi<br /> Mangan (Mn) tuy khong nguy hiem nhu As nhung ngo doc Mn van co the xay ra gay roi loan<br /> boat dong than kinh vdi bieu hien rung giat dau co that doi vdi nhiing ngudi tiep xiic lau dai<br /> vdi Mn d nong dp cao [3].<br /> Quy dinh cua To chiic Y te the gidi (WHO) cho phep nong dp As trong nude uing la 10<br /> ppb, Mn la 300 ppb [4]. Theo so lieu thong ke, 51% sl gilng d Bangladet co ham lugng As<br /> vugt qua 0,05 mg/l, Chi Le la 800 mg/l va Dai Loan la 600 mg/l [5,6]. 6 Viet Nam, tren 10%<br /> <br /> 161<br /> Tieu ban: Moi tru&ng vd Ndng lugng ISBN: 978-604-913-013-7<br /> <br /> <br /> sl gilng CO ham lugng As ldn ban 0,05 mg/L chilm 69,4% so xa da khao sat d Ha Nam, t_ai<br /> An Giang khoang 20,18% gilng co ham lugng As tren 100 ppb [7]. Kit qua phan tich mau<br /> nude ngim d mgt so khu vuc tren dia ban huyen Thanh Tri, Phap Van deu co ham lugng asen<br /> cao hon miic cho phep hang chuc lan.<br /> Viec phat triln cac cong nghe lam sach nude nhim cung cip nude sinh boat an toan va<br /> dam bao cho ngudi dan tir nguln nude ngim la rit cin thiit. C5 hau het cac nude dang phat<br /> triln ciing nhu d Viet Nam hien nay, mgt sl cong nghe xir ly nude ngam mdi. loai bo dugc sit,<br /> mgt phin mangan va asen chii chua xir li dugc hoan toan. Cac mo hinh xir li deu tren nen<br /> phuong phap xir li truyin thing (tao kit tiia/ling; keo tu/ling, lgc, hap phu, oxy hoa...) va co<br /> them nhimg vat lieu mdi dl xir li chiing [8-10]. Hieu xuat xii ly cua timg loai vat lieu con phii<br /> thuoc vao viec sir dung. Phuong phap tao kit tua sit hoac Mn co sSn trong nude ngam co the<br /> loai bo tir 70 -80 % asen; phuong phap ling kit hgp keo tu loai dugc 90%, v.v..Viec lira chpn<br /> cong nghe phii hgp nham dam bao chat lupng nude sau xir li dat tieu chuan cho phep, cong<br /> nghe don gian vdi gia thanh thap, sir dung cac nguyen lieu de kiem trong nude va co kha nang<br /> ap dung cho cac loai nguon nude khac nhau la muc dich can thiet. Vi vay, viec lira chpn<br /> quang mangan dioxit (Mn02) tu nhien va khoang diatomit lam vat lieu de xir li dong thdi ca<br /> Mn va As trong nude sinh boat la phuong an rat kha thi, dac biet la nude ngam. Kha nang hap<br /> phu As va Mn cua Mn02 va diatomit tu nhien da dugc nghien ciiu qua xac dinh dung lupng<br /> hap phu cue dai bang phuong phap hap phu tinh va hap phu dgng [11]. Trong bai bao nay, sir<br /> dung Mn02 va diatomit tu nhien de loai bo asen va mangan trong mau nude ngam tai mgt so<br /> noi (Van Phiic, huyen Thanh Tri, Ha Noi). Ket qua nghien ciiu cho thay, hai loai vat lieu nay<br /> hap phu As va Mn rat tot va loai bo chiing ra khoi nguon nude ngam vdi hieu suat cao va chi<br /> phi dau tu thap.<br /> <br /> <br /> 2. THU'C NGHIEM<br /> Tien hanh xir ly Asen, Mangan vdi cac nong do khac nhau trong mau nude gieng. Qua<br /> trinh chuan bi nhu sau:<br /> Lay lOg vat lieu, kich thudc hat 1mm (the tich tuong duong la 7,5cm^) dugc nhli vao cot<br /> hinh tru bang ong nhua chiia sin Idp bong thuy tinh d day. H6n hgp dung dich Asen va<br /> Mangan c6 nong do xac dinh dugc dua vao cot vdi luu lugng chay 1,6ml/ph diy ngugc tir day<br /> cpt len. Dung dich sau khi di qua Idp vat lieu hap phu dugc mang phan tich theo thdi gian. So<br /> do he thong xir li As va Mn trong nude ngam dugc mo ta nhu trong hinh 1:<br /> <br /> <br /> <br /> <br /> est<br /> d u n g