Adsorption calculation, Lab Reports of Physical Chemistry

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Adsorption Laboratory Report

Group 1: Arda Bassorgun and Frank Braga

The aim of this report is the determination of sorption isotherms and which model has a better fit judging by the correlation coefficient. The target metal ion to be studied was 𝐶𝑟!"^ obtained from the salt 𝐶𝑟𝐶𝑙". 6 𝐻"𝑂. The stock solution should be 100mmol/L, considering the molar mass of the salt as 266.45 g/mol, the mass of salt to reach the target concentration should be 2.6645 g. The real mass weighed was 2.6625g. So, the expected concentration should be: 𝐶 =

0 , 1 𝐿 × 266 , 45 𝑔/𝑚𝑜𝑙

Converting to mmol/L we have 99,9mmol/L. With the results from ICP-OES we calculated 𝐶# ,shown in table 1. Table 1. Primary sample data for adsorption plots. Sample name df

Y

(mmol/l) C start (mmol/l) C start (mg/l) Ce (mg/l) m sorbed (mg) Adsorbent (g) stock df:1000 g

100 df: g

50 df:100 g1 100 0.686 240.704 64135.585 18287.030 458.486 0. 20 df:100 g1 100 0.007 96.282 25654.234 191.325 254.629 0. 10 df:10 g1 10 0.069 48.141 12827.117 184.920 126.422 0. 5 df:10 g1 10 0.190 24.070 6413.559 506.901 59.067 0. 2 df:10 g1 10 0.182 9.628 2565.423 486.093 20.793 0. To plot the graphs according to the models Langmuir and Freundlich, we calculated the needed variables in order to have the linearized graphs, as shown in table 2 (Langmuir) and table 3 (Freundlich). Table 2. Variables for Langmuir graph **Langmuir qe (mg.g-

ce/qe (g/L)** 1554.253 32. 902.531 20. 503.220 0. 251.336 0. 117.897 4. 41.322 11.

After plotting the linear fittings, R^2 values are for Langmuir and Freundlich Model are 0. and 0.46, respectively. Since R^2 value of Langmuir model is higher than Freundlich model, it is a better fitting for our laboratory data. Therefore, Langmuir model is selected for the rest of calculations. Table 4. Langmuir Model Linear Fit Parameters Therefore, maximum adsorption capacity (qmax) and affinity of the sorbent for Cr (KL) values are given below. Table 5. Langmuir Model Parameters Langmuir qmax (mg/g-1) KL (L/mg) 166.667 0.