Andanastuti Muchtar
Jabatan Kejuruteraan Mekanik & Bahan, Fakulti Kejuruteraan & Alam Bina, Universiti Kebangsaan Malaysia, 43600 UKM Bangi Selangor Darul Ehsan, Malaysia

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PROSPEKTIF LEMPUNG ALAM CENGAR SEBAGAI ADSORBEN POLUTAN ANORGANIK DI DALAM AIR: KAJIAN KINETIKA ADSORPSI KATION CO(II) Muhdarina, Muhdarina; Mohammad, Abdul Wahab; Muchtar, Andanastuti
Reaktor Volume 13, Nomor 2, Desember 2010
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (364.858 KB) | DOI: 10.14710/reaktor.13.2.81-88

Abstract

Kemampuan lempung alam Cengar untuk melepaskan kation Co(II) dari air limbah model telah diuji dengan proses adsorpsi. Lempung alam Cengar diimpregnasi dengan larutan garam ammonium 1 molar untuk meningkatkan kemampuan adsorpsinya. Kapasitas adsorpsi kation Co(II) oleh lempung Cengar yang diimpregnasi meningkat di bawah pengaruh waktu kontak dan menurun dengan temperatur. Beberapa model kinetika yaitu order-pertama pseudo, order-kedua pseudo, model Elovich dan difusi intra-partikel telah digunakan untuk mengevaluasi kinetika dan mekanisme interaksi Co(II) pada lempung Cengar. Mekanisme adsorpsi Co(II)-lempung Cengar mengikuti kinetika order-kedua pseudo pada waktu perolehan adsorbat maksimum 120 menit. Dengan model Elovich didapatkan adsorben lempung Cengar memiliki permukaan yang heterogen. Energi aktivasi proses adsorpsi juga dievaluasi di bawah pengaruh temperatur dan didapatkan energi aktivasi yang negatif.
Deagglomeration of High Purity Fine Alumina Powder via pH Control Muchtar, Andanastuti; Wati, Norazmira; Jaafar, Nor Azri
ASEAN Journal of Chemical Engineering Vol 2, No 1 (2002)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1011.988 KB) | DOI: 10.22146/ajche.50803

Abstract

This paper presents results from a study on the effect of the pH of suspensions on the deagglomeration of a high-purity (99.99%), fine-grained alumina powder. The pH of the suspension was varied between pH 2 and 3. It is the aim of the study to determine the best pH for a successful dispersion of the alumina powders in the suspension. A series of rheological studies and analytical work under Scanning Electron Microscopy were conducted. It was found that the best pH was pH 2. Data obtained from rheological studies using a viscometer showed that the alumina suspension prepared at pH 2 was least viscous, which may be taken as a negative indicator of the presence of agglomerates. This hypothesis is validated by visual inspection using SEM. For the pH 2 samples, a successful removal of the agglomerates in the green compact has encouraged the sinterability of the samples and thus, resulted in an earlier sintering process at a low-firing temperature. In addition, the sintering characteristics and microstructures of the samples prepared with a pH 2 suspension are also presented.