The potential of the Senegal date palm ( <i> Phoenix reclinata </i> ) seed bio-char to remove chromium (VI) ions from aqueous solutions by adsorption was investigated. Adsorption experiments were performed on the tannery effluent and standard aqueous solutions of chromium (VI) for varying adsorbent doses, contact times, pH, temperatures, and interfering anionic ions by batch mode. <i> Phoenix reclinata </i> seeds (PRS) bio-char was used in the investigation and the residual chromium (VI) was determined using the atomic absorption spectrophotometer (AAS). Results showed that the bio-char removed up to 86% of chromium (VI) ions in the effluent at pH 2. The highest percentage adsorption registered was 97% in an aqueous solution of chromium (VI) at pH 1 and this dropped to less than 10% at pH greater than 2. A general increase in adsorption with the increase in temperature was observed but reduced when the temperature was raised beyond 60 ° C. The presence of interfering anions caused a reduction in the adsorption of chromium (VI) ions. The adsorption process fitted both Langmuir and Freundlich adsorption models and the maximum adsorption capacity, <i> Q o </i> , was 0.6593 mg/g. Thus, PRS bio-char can therefore be used by industries and institutions like secondary schools to treat effluents that contain chromium (VI).
Gardea-Torresdey, J.L., Tiemann, K.J. and Armendariz, V. (2000) Characterization of Cr(VI) Binding and Reduction to Cr(III) by Agricultural Byproducts of Avena monida (Oat) Biomass. Journal of Hazardous Materials, 80, 175-188. https://doi.org/10.1016/S0304-3894(00)00301-0
Nameni, M., Moghadam, R.A. and Arami, M. (2008) Adsorption of Hexavalent Chromium from Aqueous Solutions by Wheat Bran. International Journal of Environmental Science and Technology, 5, 161-168. https://doi.org/10.1007/BF03326009
Oguttu, H.W., Bugenyi, F.W., Leuenberger, H., Markus, W. and Bachofen, R. (2008) Polution Menacing Lake Victoria: Quantification of Point Sources around Jinja town, Uganda. Water SA, 34, 89-98. https://doi.org/10.4314/wsa.v34i1.180865
United Nations Industrial Development Organistation (UNIDO) (2002) The Leather Sector in Uganda.
Muwanga, A. and Barifaijo, E. (2006) Impact of Industrial Activities on Heavy Metal Loading and Their Physico-Chemical Effects on Wetlands of Lake Victoria Basin (Uganda). African Journal of Science and Technology, 7, 51-63. https://doi.org/10.4314/ajst.v7i1.55197
Li, Q., Zhai, J., Zhang, W., Wang, M. and Zhou, J. (2007) Kinetic Studies of Adsorption of Pb(II), Cr(III) and Cu(II) from Aqueous Solution by Sawdust and Modified Peanut Husk. Journal of Hazardous Materials, 14, 163-167. https://doi.org/10.1016/j.jhazmat.2006.06.109
Verma, A., Chakraborty, S. and Basu, J.K. (2006) Adsorption Study of Hexavalent Chromium Using Tamarind Hull-Based Adsorbents. Separation and Purification Technology, 50, 336-341. https://doi.org/10.1016/j.seppur.2005.12.007
Lubanga, C., Ntambi, E. and Adaku, D. (2017) Potential of Artocarpus Heterophyllus Seed Powder in the Adsorption of Chromium (VI) from Aqueous Solution. Journal of Water Resource and Protection, 9, 614-628. https://doi.org/10.4236/jwarp.2017.96041
APHA (2005) SM 3111B. Standard Methods for Examination of Water and Waste Water. Centennial Edition, American Public Health Association, Washington DC.
Harris, D.C. (2007) Quantitative Chemical Analysis. W.H. Freeman and Company, USA.
Skoog, D., West, D., Holler, F. and Crouch, S. (2004) Fundamentals of Analytical Chemistry. 8th Edition, Thomson Learning Academic Centre, USA
Nechiporenko, G.N. (1958) Determination of Sulphate Ions by Titration with Lead Nitrate Using Dithizone as Indicator. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science, 7, 337-340. https://doi.org/10.1007/BF00913990
Szabó, Z.G. and Barth, L. (1950) Titrimetric Determination of Nitrates with an Equivalent Ratio of 1:8. Nature, 166, 309. https://doi.org/10.1038/166309a0
Baral, S.S., Das, S.N. and Rath, P. (2006) Hexavalent Chromium Removal from Aqueous by Adsorption on Treated Sawdust. Biochemical Engineering Journal, 13, 216-222. https://doi.org/10.1016/j.bej.2006.08.003
Arshadi, M., Amiri, M.J. and Mousavi, S. (2014) Kinetic, Equilibrium and Thermodynamic Investoigations of Ni(II), Cd(II), Cu(II) and Co(II) Adsorption on Barley Straw Ash. Water Resources and Industry, 6, 1-17. https://doi.org/10.1016/j.wri.2014.06.001
Mina. G., Hassan, H. and Maryam, M. (2011) Hexavalent Chromium Removal from Aqueous Solution via Adsorption on Granular Activated Carbon: Adsorption, Desorption, Modeling and Simulation Studies. ARPN Journal of Engineering and Applied Sciences, 6, 10-18.
National Environment Management Authority (NEMA) (1999) The National Environment (Standards for Discharge of Effluent into Water and Land) Regulations.
Friedl, S. (2003) What Is Eutrophication?—Definition, Causes and Effects. https://study.com/academy/lesson/what-is-eutrophication-definition-causes-effects.html
Mohan, D., Pittman Jr., C.U., Bricka, M., Smith, F. and Yancey, B. (2007) Sorption of Arsenic, Cadmium and Lead by Chars Produced from Fast Pyrolysis of Wood and Bark During Bio-Oil Production. Journal of Colloid and Interface Science, 310, 57-73. https://doi.org/10.1016/j.jcis.2007.01.020
Pandey, P.K, Sharma, S.K. and Sambi, S.S. (2010) Kinetics and Equilibrium Study of Chromium Adsorption on Zeolite NaX. International Journal of Environmental Science and Technology, 7, 395-404. https://doi.org/10.1007/BF03326149
Lakshmipathiraj, P., Umamaheswari, S., Bhaskar, R.G., Prabhakar, S., Caroling, G., Kato, S. and Kojima, T. (2011) Studies on Adsorption of Cr(VI) onto Strychnos potatorum Seed from Aqueous Solution. Environmental Progress & Sustainable Energy, 32, 35-41. https://doi.org/10.1002/ep.10595
Arivoli, S., Nandhakumar, V., Saravanan, S. and Sulochana, N. (2009) Adsorption Dynamics of Copper Ion by Low Cost Activated Carbon. The Arabian Journal for Science and Engineering, 34, 1-12.
Argun, M.E., Dursun, S., Ozdemir, C. and Karatas, M. (2006) Heavy Metal Adsorption by Modified Oak Sawdust, Thermodynamics and Kinetics. Journal of Hazardous Materials, 141, 77-85. https://doi.org/10.1016/j.jhazmat.2006.06.095
Langmuir, I. (1918) The Adsorption of Gases on Plane Surface of Glass, Mica and Platinum. Journal of the American Chemical Society, 40, 1361-1403. https://doi.org/10.1021/ja02242a004
Haghseresht, F. and Lu, G. (1998) Adsorption Chatacteristics of Phenolic Compounds onto Coal-Reject-Derived Adsorbents. Energy & Fuels, 12, 1100-1107. https://doi.org/10.1021/ef9801165
Bishnoi, N.R., Bajaj, M., Sharma, N. and Gupta, A. (2004) Adsorption of Cr(VI) on Activated Rice Husk Carbon and Activated Alumina. Bioresource Technology, 91, 305-307. https://doi.org/10.1016/S0960-8524(03)00204-9
Oliveira, E.A., Montanher, S.F., Andrade, A.D., Nobrega, J.A. and Rollemberg, M.C. (2005) Equilibrium Studies for the Sorption of Chromium and Nickel from Aqueous Solutions Using Raw Rice Bran. Process Biochemistry, 40, 3485-3490. https://doi.org/10.1016/j.procbio.2005.02.026