Pillared Cengar clay have been synthesized by two methods, first clay suspension is directly mixed into aqueous solution of hydroxy-aluminum polycations (WK) and second by mixing the clay suspension into the solution of sodium acetate and hydroxy-aluminumpolycations (SAK) sequentially. Both clays were calcined in air on atmospheric condition. Diffraction pola, surface morphology and cationexchange capacity of the pillared clays were characterized using X Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) andvisible spectrophotometry methods, respectively. The pillared clays showed increases of basal spacing from 3.57 Å to 4.55 Å and smectiteas a new mineral. Morphology of SAK has more heterogeneous surface with small plates and agglomeration of grains compare with WKwhich small plates. Adsorption of aqueous cation of Cu 2+ were studied on various variables of initial concentration as well as temperatures.As the result, adsorption of cation Cu 2+ on pillared Cengar clay is corresponding to Freundlich isotherm, while the adsorption capacity ofWK on cation Cu 2+ is slightly lower than SAK. The thermodynamic aspect, the WK is reflected possessed exothermic processes withnegative entropy, increased in Gibbs energy and non spontaneous, while the SAK possessed endothermic processes having positive entropy,decreased in Gibbs energy and non spontaneous.

Abstrak 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 PENDAHULUANKeberadaan polutan logam berat di dalam badan air merupakan masalah lingkungan saat ini yang secara signifikan memberi dampak negatif terhadap kualitas sumber air karena material ini bersifat toksik dan tidak terbiodegradasi. Peningkatan konsentrasi logam berat di lingkungan menyebabkan logam-logam tersebut terkumpul di dalam rantai kehidupan airtumbuhan -hewan -manusia sehingga menjadi ancaman yang luar biasa bagi metabolisme kehidupan. Karena itu, adanya logam berat di dalam air akan membahayakan kesehatan karena daya racunnya yang tinggi (Naiya et al., 2009). Prayitno (2008 merekomendasikan setidaknya ada dua tindakan yang 81

Limbah pelepah sawit (LPS) dihasilkan secara periodik dari perkebunan kelapa sawit. Keberadaan LPS ini berpeluang digunakan sebagai bahan baku adsorben. LPS telah diubah menjadi arang aktif pelepah sawit (APS) melalui langkah karbonisasi pada temperatur 600oC selama waktu bervariasi (30, 60, dan 120 menit). APS yang diperoleh dilakukan analisis kadar air, abu dan zat menguap. APS juga dikarakterisasi dengan FTIR untuk menentukan gugus fungsi, keasaman permukaan dengan tirasi Bhoem serta SEM untuk mendeteksi morfologi permukaan. Kemampuan APS untuk menjerap asam lemak bebas (ALB) dari CPO dipelajari pada waktu adsorpsi dan dosis adsorben yang bervariasi. Hasil penelitian menunjukkan bahwa semua APS memiliki kadar air, abu dan zat menguap yang sangat rendah, sehingga memenuhi SNI 06-3730-1995. Gugus fungsi yang dimiliki APS di antaranya C-O, O-H, C-O-C, C=O, C-C (aromatik) dan C-H. APS mengandung 14 mmolg-1 total asam dengan mayoritas asam fenolat sebanyak 12,3 mmolg-1, sisanya sebagai asam karboksilat dan laktonat. Morfologi permukaan arang aktif membentuk rongga-rongga dengan ukuran yang semakin besar dan tersusun rapat seiring dengan lamanya waktu karbonisasi. Hasil uji adsorpsi ALB yang paling baik ditunjukkan oleh APS60 yang mampu menjerap hingga 77,8% ALB pada waktu adsorpsi 60 menit dan 1 g  dosis adsorben. Dengan demikian, LPS layak dikembangkan menjadi arang aktif dan digunakan sebagai adsorben untuk mengurangi kadar asam lemak bebas dalam CPO.

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Birnessite-type manganese oxide is multifunction material that has been used in various application and the characteristic depends heavily upon its preparation method. In this study, birnessite-type manganese oxide was synthesized using the reaction between KMnO4 (oxidant) and two different reducing agents i.e., citric acid and oxalic acid via a solvent-free method. The characterization of the birnessite was carried out using X-Ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX), and Surface Area Analyzer (SAA). Birnessite from this variation of reducing agents showed different levels of crystallinity, diverse morphology, crystal size, and surface area. The birnessite-type was then applied as a catalyst for the degradation of Palm Oil Mill Effluent (POME) with hydrogen peroxide (H2O2) as an oxidant to reduce the concentrations of Chemical Oxygen Demand (COD). The maximum reduction in COD concentration was obtained using the catalyst concentration of 400 and 800 mg/L for reducing agent of as-synthesized catalyst citric acid and oxalic acid. Birnessite-type manganese oxide shows potential as a catalyst in the degradation of POME with citric acid as reducing agents showed better degradation in reducing COD values.

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Sugarcane Bagasse can be used as an adsorbent both under natural conditions and modified by chemical activation using sodium hydroxide (NaOH). Activation of sugarcane bagasse with NaOH was carried out at variations of 5:1, 10:1, and 20:1 (w/w). The absorption ability of bagasse adsorbent to methylene blue solution was carried out with the parameters of variation of contact time (60, 90, 120, 150, and 180 minutes), adsorbate concentration (20, 30, 40, 50, and 60 ppm) and temperature (30, 40, 50, and 60 oC). The adsorbent's characterization included determining the functional groups using FTIR, morphology, and mass of elements using SEM-EDX, and determining the surface area and volume of adsorbent pores using the BET methods. The highest adsorption percentage results were found in the NASB10:1 adsorbent at 99.50%. The optimum conditions for the NASB10:1 adsorbent are with a contact time of 120 minutes, an adsorbate concentration of 50 ppm, and a temperature of 30 oC or 303 K. The NASB10:1 adsorbent has the highest surface area compared to other adsorbents, namely 2.803 m2/g so that it can perform the maximum absorption of methylene blue.