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Adsorption of La3+ and Dy3+ ions on biohydroxyapatite obtained from pork bones gasified with steam

Szczepaniak W., Zabłocka-Malicka M., Pasiecznik I., Pohl P., Rutkowski P.

Environment Protection Engineering

2018

Vol. 44, nr 1

29--40

Adsorption of La3+ and Dy3+ from their aqueous nitrate solutions on biohydroxyapatite (BHAP) originally prepared from raw pork bones by steam gasification of has been investigated for the La3+and Dy3+ concentrations within the range of 1.44·10–4–8.06·10–3 mol/dm3 and 2.71·10–5 5.68·10–3 mol/dm3, respectively. It was found that saturation of the lanthanide uptake occurred at 0.0625 moles of Ln3+ per mole of BHAP. Two model isotherms, i.e., Langmuir (qe = qmCe/((1/KL) + Ce)) and Freundlich (logqe = logKF + (1/n)logCe), were used to fit the adsorption data. The following isotherm parameters were found for La3+: qm = 0.1265 mol/kg, KL = 2701 dm3/mol, n = 5.61, KF = 0.283 (mol/kg)·(dm3/mol)1/n and for Dy3+: qm = 0.1223 mol/kg, KL = 3635 dm3/mol, n = 5.82, KF = 0.306(mol/kg)·(dm3/mol)1/n. A better correlation was found for the Freundlich model. A relatively high value of the n parameter in the Freundlich equation suggests heterogeneous chemisorption of lanthanide ions.

Removal of 2,4,6-trichlorophenol from aqueous solutions using agricultural waste as low-cost adsorbents

Kuśmierek K., Świątkowski A., Dąbek L.

Environment Protection Engineering

2017

Vol. 43, nr 4

149--163

Agricultural waste products including sunflower seed hulls, pumpkin seed shells, walnut shells and peanut shells were used as low-cost adsorbents for the removal of 2,4,6-trichlorophenol (TCP) from aqueous solutions. The effects of adsorbent dosage, pH and ionic strength on the adsorption of TCP were investigated. The results showed that the adsorption of TCP was pH dependent and increased upon increasing the ionic strength of the solution. The adsorption kinetics was found to follow a pseudo-second order kinetics. The equilibrium adsorption data were fitted to the Langmuir, Freundlich and Sips isotherms and the best results were achieved with the Freundlich model. The desorption of TCP using deionized water, water/methanol mixture or 5% sodium hydroxide was also studied. The results suggest that the tested materials may be used as an effective adsorbents without any treatment or any other modification for removal of TCP from the aqueous medium.

Phosphorus and COD removal from chemically and electrochemically coagulated wastewater

Smoczyński L., Muńska K. T., Kosobucka M., Pierożyński B.

Environment Protection Engineering

2014

Vol. 40, nr 3

63--73

Wastewater coagulation and electrocoagulation were investigated as sorption processes involving colloidal sorbents such as (Al(OH)3)n, (Fe(OH)3)m and (Fe(OH)2)p. An attempt was made to fit experimental data to two popular sorption models. Based on a statistical and mathematical analysis of the obtained results, the Langmuir model of chemical adsorption was regarded more probable than the Freundlich model. The highest maximum adsorption of phosphorus in the analyzed wastewater was achieved with the use of PIX, and the lowest adsorption maxima were reported for an iron electrocoagulant. PAC was most effective in reducing COD of wastewater. PAC and PIX delivered higher adsorption maxima for compounds responsible for COD than aluminum and iron electrocoagulants.