PHOTO-REDUCTION KINETICS OF Mn021N AQUATIC ENVIRONMENTS CONTAINING HUMICACIDS

ABSTRACT The kinetics of photo-reduction of manganese(IV) oxide, Mn02 in aqueous medium, in the presence of humic acid has been investigated, including the possibility for the involvement of such radicals in the reduction. Results showed that in aqueous medium, the efficiency of the photo-reduction of Mn02 producing a soluble ionic Mn(lI} was governed strongly by an internal electron transfer within an intermediate of HA-Mn02 anion complex, resulted in the chemical adsorption of humic acid on Mn02 surface. It was observed that under solar radiation and atmosphere containing oxygen, the rate of Mn02 reduction increased considerably, by factors of about 46 and 2 respectively. Moreover, there was evidence that some radicals certainly played a role in the photo-reduction of Mn02, since radical scavenger addition significantly decreased the reduction efficiency of Mn02. In the present of an excess of propanol-2, however, which was expected to remove all OH radicals present, only about 60 %decrease in reduction efficiency were observed, suggesting that radicals other than OH radical are involved in the reduction of Mn02. It was observed further that the presence of iron(lII) in Mn02 up to 1 % (w/w) did not alter the reduction efficiency of Mn02. Keywords: Mn02 kinetics, photo-reduction, aquatic, humic acid

STUDI ADSORPSI ION Au (III) DENGAN MENGGUNAKAN ASAM HUMAT

Proses adsoprsi ion Au (III) dengan menggunakan asam humat yang telah dilakukan dengan menggunakan metode batch. Asam humat diperoleh dari hasil isolasi tanah gambut yang diambil dari Danau Rawapening Salatiga Jawa Tengah dan karakterisasinya digunakan metode spektroskopi infra merah untuk menentukan kandungan gugus fungsi yang terdapat di dalam asam humat. Hasil karakterisasi asam humat diperoleh adanyak peregangan gugus OH pada daerah 3444,64 cm-1 dan peregangan C=O dari COOH pada daerah 1637,32 cm-1. Jumlah ion Au (III) yang teradsorp mencapai 84,05% dengan waktu kontak selama 1500 menit

Adsorption of Th-232 and U-238 by y-Al2O3-Humate at Single and Competitive systems

The calculastion experiments of adsorption capacities of Th-232 and U-238 in y-Al2O3-humate at single system and competitive with Freundlich method has been done. The purpose of the research is (1) to characterize y-Al2O3-humat functional groups, (2) to know y-Al2O3-humat solubility and (3) to predict adsorption capacities of U238 and of Th-232 at adsorbent y-Al2O3-humate. Keywords: U-238, Th-232, Adsorption Freundlic

SYNTHESIS OF Mg/Al HYDROTALCITE-LIKE FROM BRINE WATER AND ITS APPLICATION FOR METHYL ORANGE REMOVAL: A PRELIMINARY STUDY

The objective of this research is to synthesis of Mg/Al hydrotalcite-like (Mg/Al HTlc) from brine water and its application as a methyl orange (MO) removal. The research initiated with the synthesis of Mg/Al HTlc from brine water, which is well known as the desalination process wastewater. Characterization of the Mg/Al HTlc synthesized was confirmed through X-ray Diffraction and FT-IR Spectroscopy. The determination of optimum acidity, adsorption rate, and energy and capacity adsorption were studied. The result showed that pH 4 was the optimum acidity for the adsorption of MO on Mg/Al HTlc. MO was adsorbed at pseudo-second order adsorption rate of 1.03 × 105 g mol-1 min-1 on the Mg/Al HTlc. The adsorption data fitted well into the linearly transformed Freundlich equation. Keywords: adsorption, brine water, methyl orange, Mg/Al hydrotalcite-lik

Studi Kinetika dan Adsorpsi Zat Warna Kation (Metilen Biru) dan Anion (Metil Orange) pada Magnetit Terlapis Asam Humat: Adsorption and Kinetic Studies of Cationic (Methylene Blue) and Anionic (Methyl Orange) Dyes onto Magnetite Coated with Humic Acid

Sintesis magnetit terlapis asam humat (Fe3O4–HA) telah dilakukan untuk adsorpsi dari dua jenis zat warna, yaitu metilen biru (MB) dan metil orange (MO). Penelitian ini diawali dengan ekstraksi asam humat (HA) yang diperoleh dari hasil isolasi tanah gambut Rawa Pening, Ambarawa, Jawa Tengah dan dilanjutkan dengan sintesis Fe3O4–HA menggunakan metode kopresipitasi dengan agen pengendap NH4OH pada campuran garam FeSO4•7H2O, FeCl3•6H2O dan HA hasil ekstraksi. Fe3O4–HA hasil sintesis kemudian dikarakterisasi dengan spektroskopi FTIR dan difraktogram XRD. Proses adsorpsi dilakukan pada waktu keseimbangan optimum MB dan MO dengan menggunakan kinetika adsorpsi orde satu semu, orde dua semu, dan kinetika Santosa. Hasil penelitian menunjukkan bahwa adsorpsi MB dan MO oleh Fe3O4–HA mengikuti model kinetika adsorpsi orde dua semu dengan nilai konstanta keseimbangan adsorpsi (k) secara berurutan adalah 107304,348 L mol-1 untuk MB, dan 80361,011 L mol-1 untuk MO. Data adsorpsi ini diperoleh pada kondisi pH optimum pada MB dan MO secara berurutan pada pH 7 dan 2, serta tercapai waktu keseimbangan untuk MB dan MO secara berurutan pada 30 dan 15 menit

Mg/Al HYDROTALCITE-LIKE SYNTHESIZED FROM BRINE WATER FOR EOSIN YELLOW REMOVAL

Attempts to synthesis of Mg/Al HTlc using magnesium from several raw material resources are widely investigated. One of raw material would purpose as source of magnesium to synthesis of Mg/Al HTlc is brine water which is well known as the desalination process wastewater. Mg/Al HTlc are widely investigated for their potential applications in research and industrial processes as adsorbents, anionic exchange, catalysts and /or catalyst precursors for the preparation of inorganic materials and pharmaceutical industry excipients. As adsorbents, Mg/Al HTlc are receiving greater interests in the environmental community due to their high adsorption capacity. However, there is no literature available on the synthesis of Mg/Al HTlc from brine water except from artificial seawater. The objective of this research is to synthesis of Mg/Al HTlc from brine water and its ability tested for eosin yellow (EY) removal. Characterization of the Mg/Al HTlc synthesized was confirmed through X-ray Diffraction and FT-IR Spectroscopy. The effect of various experimental parameters was investigated using a batch adsorption technique. In this manner, the adsorption isotherms, adsorption kinetics, and pH effects upon EY adsorption on Mg/Al HTlc were examined. The result showed that EY data fit well with the pseudo-second order kinetic model. The isothermal data could be well described by the Freundlich equation. The adsorption capacity was 2.41 × 10-1 mol g-1, and adsorption energy of EY was 24.89 kJ mol-1. Keywords: Mg/Al hydrotalcite-like, brine water, adsorption, eosin yellow, adsorption capacit

SISTEM PENURUNAN KADAR KROM (III) LIMBAH CAIR INDUSTRI PENYAMAKAN KULIT DENGAN KOMBINASI PRESIPITASI MENGGUNAKAN NATRIUM HIDROKSIDA DAN ADSORPSI MENGGUNAKAN BAGASE FLY ASH

Wastewater in the tannery industry is the main waste due to the use of a great amount of water and chemical substances in the process. Wastewater which contains chromium from the tanning materials potentially causes physical and chemical changes in the environment. Chromium is harmful heavy metal which is non-degradable and able to cause danger towards environment and human health. Therefore, it is important to employ treatments before discharging the wastewater to the environment. One of the known methods to reduce the content of heavy metal is precipitation using sodium hydroxide. However, precipitation alone can not meet the strict quality standard for tannery industrial wastewater. Adsorption using bagasse fly ash (BFA) is a key promising tertiary method to achieve the high treatment standard. BFA is a low cost adsorbent since it is prepared from solid waste from sugar industry. This research aims to study optimum operating condition of the implementation of a combination of precipitation and adsorption methods for reducing chromium (III) in the tannery industrial wastewater.Initially, this study used synthetic waste to obtain optimum conditions for adsorption method. The optimum conditions were then tested using real waste from tannery industry. Synthethic waste used in this process was Cr(NO3)3.9H2O. Adsorption process used both activated BFA as well as raw (un-activated) BFA. Concentration of crom (III) in the filtrate was determined by AAS (Atomic Absorption Spectrocopy). Parameters of the study were pH of the precipitation, and pH of the adsorption.Results of this study showed that the optimum pH to chrom (III) concentration reduction is achieved from the combination of precipitation at pH of 8 and adsorption at pH of 5. The effectiveness of the concentration reduction of chromium using combination of both of these methods managed to lower the concentration of chromium from initial concentration of 544 mg/l to 0,18 mg/l (using activated BFA), with the effectiveness of chromium reduction 99.97%. This result complies with the standard based on Yogyakarta Governor's decree number 7/2010 about wastewater quality standard for wet blue leather industrial activities, which is 0,4 mg/l

PEMANFAATAN SENYAWA POLI-MONOALILOKST KALIK[6]ARENA SEBAGAI ANTIDOTUM KERACUNAN KADMIUM PADA MENCIT = (The Utilization of Poly-monoallyloxy-calix{6Jarene as Antidote on Cadmium Intoxication in Mice)

Pada penelitian ini akan dipelajari kemampuan dari senyawa poli-monoaliloksi-kaliks[6]arena (PMK[6]H) sebagai antidotum keracunan Cd pada mencit. Penelitian ini mengikuti rancangan acak lengkap dengan menggunakan mencit jantan, galur Balb/C, sehat, umur 2-3 bulan dan mempunyai bobot badan yang seragam. Subjek uji sebanyak 30 ekor dikelompokkan menjadi 6 kelompok. Kelompok 1 adalah kelompok mencit yang diberi pakan normal dan larutan CMC 0,5%. Kelompok 2 (kontrol negatif) diberi pakan normal dan dicekoklarutan CdCl2 (3,15 mg selama 14 hari pada setiap pagi). Kelompok 3 adalah kelompok kontrol positif (kontrol antidotum) dan kelompok 4-6 adalah kelompok eksperimen.Kelompok3-6 diberipakan normal dan dicekoklarutanCdCh selama 14 hari pada setiap pagi dan sore harinya diobati dengan dimerkaprol (0,65 mg/Kg BB) untuk kelompok 3 dan PMK[6]H untuk kelompok eksperimen dengan dosis masing-masing 0.220,65dan 1,95 mg/Kg BB dalam CMC 0,5%. Pengamatan gejala toksik dilakukan selama 14 hari. Pada akhir masa uji, mencit dikorbankan untuk selanjutnya diambil ginjal dan hatinya untuk diukur kadar Cd dengan menggunakan spektrofotometer serapan atom (AAS) dan untuk pengamatan histopatologi. Hasil penelitian menunjukkan adanya penurunan kadar Cd dalam ginjal mencit pada kelompok 3-6 yaitu berturut-turut sebesar 14,9815,2230,92dan 45,61 %. sedangkan kadar Cd dalam hati mengalami penurunan masingmasing sebesar 23,3725,7931,82dan 35,66 %. Berdasarkan data tersebut, maka PMK[6]H dapat menurunkan kadar Cd dalam ginjal dan hati mencit yang telah diracuni dengan CdC2 bahkan pada tingkat dosis yang sama, PMK[6]H memberikan penurunan kadar Cd yang lebih besar dari dimerkaprol

Comparison Study of PHBA-intercalated Mg/Al-LDH and PHBA-immobilized Mg/Al-LDH: Characterization and Application for [AuCl4]̄ Removal from Solution

Synthesis of p-hydroxybenzoic acid (PHBA)-intercalated Mg/Al-LDH and PHBA-immobilized Mg/Al-LDH have been conducted. PHBA-intercalated Mg/Al-LDH hybrid was synthesized by co-assembly process of Mg/Al-LDH nanosheets and PHBA anions. PHBA-immobilized Mg/Al-LDH was prepared by indirect synthesis, where PHBA anions were attached on surface of the Mg/Al-LDH material. Characterization by X-ray Diffraction showed that the PHBA-intercalated Mg/Al-LDH hybrid has the lattice parameter of a=3.02 Å, lattice parameter of c=46.77 Å and basal spacing d003=15.14 Å, where PHBA has been intercalated in interlayer of the hybrid. The PHBA-immobilized Mg/Al-LDH has lattice parameter of a=3.06 Å, lattice parameter of c=23.70 Å and basal spacing d003=7.90 Å. The analytical result confirmed that PHBA has been attached on surface of the hybrid for PHBA-immobilized Mg/Al-LDH. The optimum 10 mL of [AuCl4]‾ 100 mg L-1 removal condition of both hybrids were reached at pH 3. The optimum interaction time of [AuCl4]‾ and PHBA-intercalated Mg/Al-LDH hybrid was 250 minutes, respectively, while that for [AuCl4]‾ and PHBA-immobilized Mg/Al-LDH was 150 minutes. Removal of [AuCl4]‾ by PHBA-intercalated Mg/Al-LDH hybrid followed pseudo second order kinetic, whereas by PHBA-immobilized Mg/Al-LDH followed pseudo first order kinetic. Characterization using stereo photomicroscope confirmed that [AuCl4]‾ could be reduced  to Au  metal by both hybrids

DETERMINATION OF RATE CONSTANT AND STABILITY OF ADSORPTION IN COMPETITIVE ADSORPTION OF Cr(III) AND Cd(II) ON HUMIC ACID BY USING THE NEW MODEL OF KINETIC FORMULATION

Determination of rate and stability constants of adsorption in competitive adsorption of Cr(III) and Cd(II) on humic acid by using the new model of kinetic formulation has been done. The new model based on assumption that those adsorption was first order adsorption rearched equilibrium. Humic acid was isolated from Peat moss of Silaut- West Sumatra by modificated Schnitzer method. Humic acid characterization was conducted by using infrared spectrophotometer with KBR pellet method. The experiment of kinetic adsorption was conducted in batch system reactor using erlenmeyer at 25 ± 0.01 oC of water steam bath and in a series of sampling procedure. Initial concentration of both Cr(III) and Cd(II) was 4x10-4 M. Thirty milligrams of humic acid was added to 200 mL of metal solution, and then stirred continuously. At the fixed periode of time, 10 mL of sample was taken using a syringe, then filterd with 0.45 µm filter paper. Concentration of Cr(III) and Cd(II) in the filtrate was determinated by AAS, while that was adsorbed by humic acid was equal to difference between initial and equilibrium concentration. It was concluded that competitive adsorption of Cr(III) and Cd(II) on humic acid was first order adsorption rearched equilibrium as proposed in this research. Adsorption rate constant of Cr(III) on humic acid  at competitive condition was greater than of Cd(II), but on the contrary for stability constant (K). Competition between Cr(III) and Cd(II) to interact with the active side of humic acid was dominated by Cr(III).   Keywords: rate constant, stability and competitive adsorptio