{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Separation Process Principles- 2n - Seader & Henley - Solutions Manual

Adsorption equilibrium data at 547 k for

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 21 x 105 cm2/g or 52.1 m2/g This is much smaller than the values given for silica gel in Table 15.2. Exercise 15.5 Subject: Maximum ion-exchange capacity of a resin. Given: Ion-exchange resin made from 8 wt% divinylbenzene and 92 wt% styrene. Find: Maximum ion-exchange capacity in meq/g resin. Analysis: Compute the moles of each aromatic component per 100 grams of resin: Styrene Divinylbenzene Total MW 104.14 130.18 grams 92 8 100 gmol 0.8834 0.0615 0.9449 Therefore, need 0.9449 mol H2SO4 or 0.9449(81.07) = 76.6 g. Total resin weight after sulfonation = 100 + 76.6 = 176.6 g. Maximum ion-exchange capacity = 0.9449(1000)/176.6 = 5.35 meq/g of resin. Exercise 15.6 Subject: Fitting adsorption data to linear, Freundlich, and Langmuir isotherms and computing the heat of adsorption. Given: Silica gel adsorbent with: surface area = Sg = 832 m2/g, pore volume = Vp = 0.43 cm3/g, particle density = ρp = 1.13 g/cm3, and average pore diameter = dp = 22 angstroms. Equilibrium adsorption data for pure benzene vapor at 4 different temperatures as follows: q, moles adsorbed /g gel x 105: p, partial pressure, atm 70oC 90oC 110oC 130oC 0.0005 14.0 6.7 2.6 1.13 0.0010 22.0 11.2 4.5 2.0 0.0020 34.0 18.0 7.8 3.9 0.0050 68.0 33.0 17.0 8.6 0.0100 88.0 51.0 27.0 16.0 0.0200 78.0 42.0 26.0 Find: (a) For each temperature, best fits of the data to (1) linear, (2) Freundlich, and (3) Langmuir isotherms. Which give a reasonable fit? (b) Do data represent less than a monolayer? (c) Heat of adsorption, with comparison to heat of vaporization of benzene. Analysis: The regression program of POLYMATH can be used to do nonlinear curve fits or a spreadsheet program can be used to do least squares curve fits on the linearized isotherms. For the former, the following results are obtained for fitting Eqs. (15-16), (15-19), and (15-24). Somewhat different results would be obtained with the linearized equations (15-20) and (15-25). (1) q = kp Linear (2) q = kp1/n Freundlich (3) q = Kqmp/(1 + Kp) Langmuir Temperature, o C 70 90 110 130 Linear: k 0.1011 0.0431033 0.0229401 0.0138306 Freundlich: k 0.0132915 0.00944163 0.00653397 0.00595422 n 1.71882 1.57209 1.43190 1.25461 The linear equation is a poor fit for all 4 temperatures. The Freundlich equation a reasonably good fit for all 4 temperatures. The Langmuir equation gives the best fit for all 4 temperatures. Langmuir: K 188.18 67.55 50.0327 27.4455 qm 0.0013584 0.0013337 0.00083383 0.00073471 Exercise 15.6 (continued) Analysis: (continued) (b) The surface area covered by one adsorbed molecule is given by Eq. (15-8), where for benzene, M = 78.11 and the liquid density, from Fig. 2.3, ranges from 0.82 cm3/g at 90oC to 0.76 cm3/g at 130oC. At 90oC, M α = 1.091 N Aρ L 2/3 7811 . = 1091 . 6.023 × 1023 (0.82) 2/3 = 319 × 10 −15 cm2 . From the data, the maximum experimental adsorption is 0.00088 moles benzene/g silica gel. This is a coverage of 0.00088(6.023 x 1023)(3.19 x 10-15) = 1.69 x 106 cm2/g or 169 m2/g. This is far less than the given...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern