Attapulgite calcined at 973.15K was characterized and utilized as an adsorbent for the removal of heavy metals and neutralization of acid mine drainage (AMD) from a gold mine. Batch adsorption experiments were carried out using a thermostatic shaker. Activated attapulgite showed that it can neutralize AMD as it raised the pH from 2.6 to 7.3 after a residence time of 2 h. Metal ion removal after 2 h was 100% for Cu (II), 99.46% for Fe (II), 96.20% for Co (II), 86.92% for Ni (II) and 71.52% for Mn (II) using a 2.5% w/v activated attapulgite loading. The adsorption best fit the Langmuir isotherm; however, Cu (II), Co (II), and Fe (II) data fit the Freundlich isotherm as well. Calcination at 973.15 K resulted in the reduction of the equilibrium residence time from 4 to 2 h, solid loading reduction from 10 to 2.5% m/v and an increase in maximum adsorption capacity compared with unactivated attapulgite.

Acid Mine Drainage Attapulgite Calcination Adsorption Heavy Metal Removal

Younger PL, Banwart SA, Hedin RS, Mine water hydrology, pollution, remediation, Dordrecht, The Netherlands, Kluwer Academic (2002). (2002)
Stumm W, Morgan JJ, Aquatic Chemistry, 3rd Ed., Wiley, New York (1996). (1996)
Expert Team of the Inter-Ministerial Committee, Mine water management in the Witwatersrand Gold Fields with special emphasis on acid mine drainage, Report to the Inter-Ministerial Committee on Acid Mine Drainage. Pretoria: Department of Water Affairs (2010). (2010)
Filion MP, Siroois LL, Ferguson K, CIM Bulletin, 83, 33 (1990)
Caraballo MA, Macias F, Rotting TS, Nieto JM, Ayora C, Environ. Pollut., 159, 3613 (2011)
Murphy CB, Spiegel SJ, Water Pollut. Federat., 54, 849 (1982)
Rios CA, Williams CD, Roberts CL, J. Hazard. Mater., 156(1-3), 23 (2008)
Zhang HB, Tong ZF, Wei TY, Tang YK, Desalination, 276(1-3), 103 (2011)
Falayi T, Ntuli F, J. Ind. Eng. Chem., http://dx.doi.org/10.1016/j.jiec.2013.07.007 (2013)
Tutu H, McCarthy TS, Cukrowska E, Appl. Geochem., 23, 3666 (2008)
Frost RL, Cash CA, Kloprogge JT, Vibrational Spectroscopy, 16, 173 (1998)
Madejova J, Komadel P, Clays Clay Min., 49, 410 (2001)
Yan W, Liu D, Tan D, Yuan P, Chen M, Spectroc. Acta Pt. A-Molec. Biomolec. Spectr., 97, 1052 (2012)
Hirsiger W, Vonmoos MM, Wiedemann HG, Thermochim. Acta, 13, 223 (1975)
Van-Scoyoc GE, Serna CJ, Ahlrichs JL, American Mineralogist, 64, 215 (1979)
Dixon JB, Weed SB, Minerals in Soil Environments, 2nd Ed. Soil Science Society of America, Wisconsin, USA (1989). (1989)
Ntuli F, Lewis AE, Chem. Eng. Sci., 64(9), 2202 (2009)
Gan F, Zhou J, Wang H, Du C, Chen X, Water Res., 43, 2907 (2009)
Ucun H, Bayhan YK, Kaya Y, Cakici A, Algur OF, Desalination, 154(3), 233 (2003)
James EH, Inorganic Chemistry Principles, Harper & Row (1978). (1978)
Juang RS, Wu FC, Tseng RL, Environ. Technol., 18, 525 (1997)
Tryball RE, Mass Transfers Operations, 3rd Ed., McGraw-Hill, New York (1980). (1980)
Bhattacharyya KG, Gupta SS, Appl. Clay Sci., 41, 1 (2008)
Okoye IP, Obi C, International Arch. Appl. Sci. Technol., 3, 58 (2012)
Gupta VK, Ind. Eng. Chem. Res., 37(1), 192 (1998)
Vieira MGA, Neto AFA, Gimenes ML, da Silva MGC, J. Hazard. Mater., 177(1-3), 362 (2010)
Balintova M, Holub M, Singovszka E, Chem. Eng. Trans., 28, 1 (2012)
Boonchom B, Youngme S, Maensiri S, Danvirutai C, J. Alloy. Compd., 454, 78 (2008)
Liu XD, Hagihala M, Zheng XG, Meng DD, Guo DX, Chin. Phys. Lett, 28, 1 (2011)
Paavo L, Jouni T, ActaChemicaScandinavica, 27, 2287 (1973)
Mohammad A, Desalination, 250, 885 (2010)
Sposito G, The Chemistry of Soils, New York, Oxford University Press (1989). (1989)