This paper was originally a public lecture text of former Minister of Religious Affairs. H. Tarmizi Taher, MD, at the Center for the Study of World Religions, Harvard University, USA., On 8 November 1995, discussed the Indonesian Muslim religious discourse in relation to inter-religious relations.DOI: 10.15408/sdi.v3i2.805
Abstract: Adsorption of procion red on natural bentonite was studied by kinetic study to know the reactivity of procion red. Kinetic adsorption was determined using batch adsorption system at various times in several concentrations of procion red. Time of adsorption was investigated at 5, 10, 20, 30, 45, 60, 90, and 120 minutes in 10, 25, 50, and 75 mg/L of procion red. The data was calculated using Langmuir-Hinshelwood kinetic equation. The diffusions process of procion red into bentonite at lower concentration was faster than at higher concentration in general with fit correlation between [(ln(Co/C))/C] vs t/C from Langmuir-Hinshelwood data. The adsorption procion red on bentonite data at various times shows Langmuir monolayer adsorption process in the surface of bentonite.Keyword: adsorption, procion red, natural bentonite, kineticAbstrak (Indonesian): Adsorpsi procion merah pada bentonit alam telah dipelajari melalui studi kinetik untuk mengetahui reaktivitas procion merah. Kinetika adsorpsi ditentukan menggunakan sistem adsorpsi simultan pada berbagai waktu dalam beberapa konsentrasi procion merah. Waktu adsorpsi dipelajari pada 5, 10, 20, 30, 45, 60, 90, dan 120 menit pada konsentrasi procion merah 10, 25, 50, dan 75 mg/L. Data dihitung menggunakan persamaan kinetika Langmuir-Hinshelwood. Proses difusi procion merah ke dalam bentonit pada konsentrasi rendah lebih cepat dibanding pada konsentrasi lebih tinggi secara umum dengan hubungan korelasi yang lurus antara [(ln(Co/C))/C] versus t/C dari data Langmuir-Hinshelwood. Adsorpsi procion merah pada bentonit dengan berbagai variasi waktu adsorpsi menunjukkan proses adsorpsi satu lapisan pada permukaan bentonit.Â Katakunci: adsorpsi, procion merah, bentonit alam, kinetikÂ
Abundant and inexpensive Indonesian natural bentonite was activated by thermal activation at 500 oC for removal of procion red dye as one of the most used synthetic dye in the traditional songket fabric production around Palembang city. Activated bentonite product was characterized by FT-IR, XRD, and thermal analysis. The adsorption process was conducted in batch adsorption system by applying various adsorption parameter condition including, initial pH condition, contact time, and initial dye concentration. The activated bentonite characterization indicates that during the activation process, the structure of the original bentonite was not changed significantly and the result of the thermal analysis revealed that thermal activation at 500 oC was draining the water content without destructing the silica-alumina framework of bentonite. The adsorption kinetics study shows that the procion red adsorption into the activated bentonite follows the pseudo-second order kinetic model. The isotherm adsorption study revealed that procion red adsorption into activated bentonite adapted the Langmuir adsorption isotherm.
Layered double hydroxides Mg/Al and Ca/Al has been synthesized by co-precipitation method with molar ratio M2+:M3+ (3:1) at pH 10. The synthesized materials were characterized by XRD and FTIR. The materials were used as adsorbent for the removal Cobalt (II) in aqueous solution. The adsorption experiments were studied through some variables adsorption such as variation of contact time, variation of temperature and variation of initial concentration. Kinetic parameters was obtained from variation of contact time. Data was analyzed by pseudo-first-order and pseudo-second-order kinetics models in linear analyses. The kinetic studies showed that the adsorption process more fitted by pseudo-second-order than pseudo-first-order based on coefficient correlation. Isotherm parameters was calculated using Langmuir and Freundlich isotherm models. The adsorption process was spontaneous and endothermic.
Ca/Al layered double hydroxides (Ca/Al LDH) was synthesized using co-precipitation method following calcination at 800 °C and was intercalated with Keggin ion [α-SiW12O40]4– to form intercalated Ca/Al LDH. Materials were characterized using XRD and FTIR spectrophotometer. Furthermore, materials were used as an adsorbent of cadmium(II) from solution. The results showed that layer material was formed completely after calcination which was indicated at diffraction 20° due to loss of water in the interlayer space. Ca/Al LDH after calcination was intercalated with [α-SiW12O40]4– ion and interlayer distance was increased from 4.25 to 4.41 Å showed that intercalation process was successfully conducted. Adsorption of cadmium(II) using Ca/Al LDH was conducted at pH 9 and intercalated Ca/Al LDH at pH 8 showed that intercalated material has slightly faster than Ca/Al LDH without intercalation probably due to slightly increasing interlayer distance of Ca/Al LDH after intercalation. The adsorption capacity of intercalated Ca/Al LDH was higher than Ca/Al LDH without intercalation at the temperature range of 30–50 °C.
Zn/Al and Zn/Fe layered double hydroxides has successfully synthesized by co-precipitation methods with molar ration 3:1. The samples were characterized using X-Ray Diffraction, Fourier Transform Infrared Spectroscopy and Surface Area using BET method. In this study, Zn/Al and Zn/Fe layered double hydroxides were used to remove direct yellow dye in aqueous solution. The experiments were carried out time variations with the aim of observing the kinetic studies. The results showed that the adsorption of direct yellow onto Zn/Al and Zn/Fe layered double hydroxides based on co-efficient correlation kinetic models more fit using pseudo-second-order than pseudo-first-order.
Synthesis of Zn-Cr layered double hydroxide intercalated with polyoxometalate K3[?-PW12O40]nH2O and K4[?- SiW12O40]nH2O was conducted successfully. The characterization of layered double hydroxide intercalated was performed using XRD and FT-IR analyses. After that layered double hydroxide intercalated used as an adsorbent of rhodamine B (RhB) dye. The results show Rhodamine-B (RhB) more effective adsorbed using the Zn-Cr adsorbent K3[?-PW12O40]nH2O than using an intercalated adsorbent K4[?-SiW12O40]nH2O because the distance between the layers is smaller. Study of kinetics showed that the adsorption process is more fits with PSO than PFO based on coefficients correlation. The adsorption process described by Langmuir isotherm models for all adsorbent. The value of enthalpy and entropy shows that the adsorption process was endothermic and negative free energy value was indicated that the process was spontaneous.
In order to minimize harmful effect of synthetic dye (direct yellow and direct violet) the capacity of Zn/Al, Zn/Cr and Zn/Fe layered double hydroxides of these contaminant was studied in this work. Batch adsorption experiment was conduct to investigate the effect of various operating parameters such as contact time, initial dye concentration and adsorption temperature in order to provide optimal condition in removal synthetic dye. Based on result, the sorption of direct dye onto LDHs followed pseudo-second-order rate model. The equilibrium adsorption data for both direct dye was fitted Freundlich isotherm model
Layered double hydroxides are composed by substitution of metal cation divalent and trivalent. Metal cation divalent and trivalent can be changed. In this work, effect metal cation trivalent (M3+) toward layer formation were studied. Synthesis of LDHs has used co-precipitation methods with molar ratio 3:1 and kept pH at 10. The result of synthesis was characterized by X-ray Diffraction (XRD) and Fourier Transform Infrared (FT-IR) analyses.