NaOH Activation Research Articles

Study on methylene blue adsorption of activated carbon made from Moringa oleifera leaf

Activated carbon was prepared from Moringa oleifera leaf by NaOH activation (ACB), and was applied to remove methylene blus (MB) from aqueous solution. The ACB was characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), and Fourier Transform-Infrared Spectroscopy (FT-IR). The isoelectric point of ACB, pHzpc = 8. Investigation of some factors affecting the adsorption capacity of ACB by the method of static adsorption results: The time to reach adsorption equilibrium is 90 min. The best adsorption pH for MB is 7, the adsorbent dosage is 1.67 g/L. The adsorption on ACB obeys isothermal absorption models of Langmuir, Tempkin and Freundlich, single layer absorption under heterogeneous suface condition, existence weak interaction between absorbent and adsorbant, determine the maximum adsorption capacity for MB of qmax = 136.99 mg / g and constant KL = 0.07 (L / mg). The MB adsorption process of ACB materials is physical adsorption, self-evolution, exothermic and follow the model of second apparent adsorption kinetics.

Preparation of highly porous activated carbons from peanut shells as low-cost electrode materials for supercapacitors

The synthesis of three-dimensional porous biomass carbons from the abundant peanut shells is investigated employing K2CO3, KCl, KOH, and NaOH as the activators for the application as low-cost electrode materials for supercapacitors. The results show that KCl-AC and K2CO3-AC are mainly composed of microporous structures, while KOH-AC and NaOH-AC show a well-developed porous structure consisting of both micropores and mesopores, and NaOH activation is more inclined to form mesopores than KOH. KOH-AC achieves the highest specific surface area of 2936.8 m2 g−1 and a relatively higher graphitization degree among these samples. At 1 A g−1, the gravimetric specific capacitances of K2CO3-AC, KCl-AC, NaOH-AC and KOH-AC are 250, 210, 284, and 339 F g−1 in the three-electrode system. The gravimetric specific capacitance of KOH-AC reaches 440 F g−1 at 0.1 A g−1 and retains 286 F g−1 at 10 A g−1. In a two-electrode system, KOH-AC exhibits a high specific energy of 39.1 W h kg−1 at a specific power of 2495.5 W kg−1. KOH-AC also shows low internal resistance and good charge and discharge performance, and high cycle stability of 80% capacitance retention is achieved for 10000 cycles at 5 A g−1.

Enhanced adsorptive removal of sulfamethoxazole from water using biochar derived from hydrothermal carbonization of sugarcane bagasse

This research work primarily focussed on the production of biochar from sugarcane bagasse through HTC followed by NaOH activation at inert atmosphere for removing SMX from water. The biochar was characterized for structural morphology and presence of functional groups. XRD and FTIR analysis confirmed that presence of aromatized graphitic structure accumulated with oxygenated functional groups are responsible for the elimination of SMX. SEM analysis portrayed the sphere-shaped structure of biochar with hydrophobic groups interior and hydrophilic groups exterior. BET isotherm revealed the active surface area equal to 1099 m2/g with high coverage of mesopores structure. Pzpc of adsorbent is evaluated to 6.5 stating that effective removal of SMX depends on ionization effects induced due to reaction medium. Kinetics study revealed the sorption of SMX followed chemical interaction pertaining to Elovich model. Isotherm studies revealed that Freundlich model fitted well stating heterogeneous mode of interaction. Immobilization of SMX on surface of ABC is due to charge assisted hydrogen bonding and π-π interaction with graphitized carbon, showing maximum sorption capacity of 400 mg/g through spontaneous reaction. The results suggested that HTC derived biochar had great adsorption affinity with respect to pH towards SMX and could be employed as an effective sorbent in cleaning water contaminants.

Statistical modeling of geopolymers from dual-alkali activation of un-calcined phosphate sludge and their potential applications as sustainable coating materials

Upcycling phosphate mining sludges to produce a green cementitious binder, called geopolymer, has recently been implemented; although interesting, a thermal activation has been required to increase their reactivity, in detriment of the energy consumption, environmental footprint and costs. This paper provides an innovative approach to phosphate sludge disposal without any thermal activation, through a dual-alkali activation of NaOH–KOH for designing sustainable geopolymer coating binder of metakaolin with up-to 50 wt% replacement by un-calcined phosphate sludge (UPS). RSM-based statistical design was undertaken to optimize and understand the influence of design factors of activator modulus (MS), ageing time and thermal curing on compressive strength, apparent porosity and water absorption as targeted properties, through polynomial models. Optimal geopolymer testing included measurements of initial-final setting time and durability against 5% NaCl, 5% Na2SO4 and 2% HCl attack up to 3 months, through the visual examination, weight loss and flexural strength.The microstructures of the optimal binder highlighted significant changes in the geopolymeric network, including the formation of hybrid type gels (N,K)-A-S-H or (C,N,K)-A-S-H, silica gel and C-A-S-H/C–S–H co-existing with an inactive filler material exerted by unreacted particles. The optimal binder with RSM methodology reached in a high compressive strength of 49.78 ± 0.30 MPa at 26 days of curing, which obviously confirmed in terms of the microstructural features. A thermal curing (50C°) looks effective to maintain a suitable setting time while achieving excellent mechanical and chemical stability in aggressive environments. In these blends, the UPS chemistry is effective to improve both the mechanical and the durability properties where it acts basically as a barrier (chemical and/or physical) owing to the dual-alkali cations (MS = 1.32) in the activation solution. This study confirms the promise of using the elaborated UPS-MK based geopolymers as sustainable coating materials, which could substantially promote a cleaner production in the construction sector and phosphate mines.

Synthesis of 3D-interconnected hierarchical porous carbon from heavy fraction of bio-oil using crayfish shell as the biological template for high-performance supercapacitors

The practical application of raw biomass in high-performance supercapacitors is mainly hindered by virtue of their relatively rare efficient storage sites and low diffusion kinetics. Herein, hierarchical porous carbons (HPCs) are synthesized from heavy fraction of bio-oil (HB) based on a hard-template method accompanied by different NaOH activation temperatures. Thanks to the favorable 3D-interconnected hierarchical porous structure, ultrahigh specific surface area (3095 m2 g−1), large total pore volume (1.66 cm3 g−1), as well as reasonable content of oxygen atoms (7.83 at. %), CSB-800 delivers a prominent gravimetric specific capacitance of 351 F g−1 (0.5 A g−1), which is considerably superior or at least comparable than previously reported for other biomass-based materials. In addition, the assembled CSB-800//CSB-800 symmetric supercapacitors can reach a superior energy density of 20 W h kg−1 at a power density of 350 W kg−1 (0.5 A g−1). The route proposed for preparing HB-based HPCs broadens a new horizon in exploring large-scale synthesis of electrode materials from industrial by-product and kitchen waste.

Experimental design via NaOH activation process and statistical analysis for activated sugarcane bagasse hydrochar for removal of dye and antibiotic

In this study, hydrochar derived from SB was activated with sodium hydroxide (NaOH) by the cold alkali activation method, to increase the number of oxygenated functional groups, as well as enhance its porosity by clearing pore blockages. Response surface methodology by central composite design (RSM-CCD) was employed to investigate the effects of NaOH activation process parameters (NaOH concentration (A), hydrochar mass ratio (B) and activation time (C)) on prepared hydrochar towards three responses; activated hydrochar (AHC) yield, tetracycline (TC) antibiotic removal and crystal violet (CV) dye removal. Through the analysis of variance (ANOVA) tests, the significance sequences of single factor affecting were B > C > A for AHC yield, A > B > C for both TC removal and CV removal. However, the significant interaction effect for both AHC yield and TC removal was observed with BC only. Meanwhile, CV removal was noticed with different result whereby two significant interaction effects (AB and AC) were observed. Through optimisation study, optimised AHC (AHCop) was generated by maximising all three responses and it was predicted to generate 54.23% yield with TC and CV adsorption capacity of 22.60 mg g−1 and 47.97 mg g−1. A relative standard deviation (R.S.D) of 1.32%, 0.97% and 2.14% (n = 3) were obtained for AHC yield, TC and CV removal, respectively. Following optimisation, AHCop was characterised by N2 adsorption-desorption isotherm analysis, Field Emission Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and Thermogravimetric analysis. In brief, the physiochemical characteristics of AHCop were observed with meso and macro pore structures, numerous microsphere-like particles with crack surfaces, abundance functional groups, strong π-π reaction and high thermal stability. The optimisation study was succeeded to develop AHCop at a higher yield and remove both TC and CV at higher adsorption capacity compared to before activation.

Calcined Low-grade Clays as Sources for Zeolite Containing Material

The continuous development and expansion of a raw material base in response to increasing environmental and technical requirements for most consumable commodities are crucial for the sustainable development of resource- and energy-intensive materials and technologies. As the sources for alkali-activated cements and zeolites, recent studies have reported the suitability of applying calcined clays with various chemical compositions, percentages, and constituent clay minerals and secondary minerals. In this article, the results of a feasibility study on the alkali activation of low-grade clays with 7.26 % montmorillonite/chlorite and 23.14 % kaolinite/montmorillonite minerals are reported. The 6M NaOH activation of clays thermally treated at 700 °C results in the formation of a hardened paste with a compressive strength of up to 5 MPa, with an N-(A)-S-H binder gel and zeolite Na2Al2Si2.5O9∙6.2H2O being the main reaction products.

Effects of chemical activating agents on physical properties of activated carbons – a commentary

Abstract Well-developed surface areas and porous structures that render high adsorption capacity are necessary for pollutant removal from wastewater by activated carbons. Activated carbons from natural resources, and agricultural and industrial waste materials are produced using chemical agents, including KOH, H3PO4, K2CO3, ZnCl2 and NaOH. This study is intended to highlight the effects of those agents on the physical properties of the activated carbons. The operating conditions, i.e., temperature, time and ratio, show an interplay towards the physical properties at varying degree. The yield, pore size, mesoporosity and surface area of activated carbons derived using different chemical agents correlate well with the impregnation ratio. Generally, the pore size, mesoporosity and surface area increase, while the yield decreases with increasing ratio (over a given range). Higher ratio and temperature are recommended for KOH, K2CO3 and NaOH activation, to endow activated carbons with greater surface area.

Rice Husk Activated Carbon with NaOH Activation: Physical and Chemical Properties

Activated carbon was produced from rice husk by activating with NaOH. Three types of samples were made at 850, 750, and 650 °C activation temperature. The properties of the samples were determined. The activated carbons have surface area of 429.82 m2 /g from 850 °C activation, 121.39 m2 /g (750 °C) and 93.89 m2 /g (650 °C). The results were higher than rice husk carbon without activation (0.23 m2 /g). The activated carbons have mesopore size (2-50 nm). Proximate and ultimate analyses of the samples were also determined. The activation process increased the carbon content of the samples. Physical characteristics of the activated carbons were shown from the XRD analysis. FTIR demonstrated the different functional of the rice husk carbon and activated. The SEM images showed the pores on the surface of the activated carbon due to the NaOH activation.

Influence of Dry Milling on Phase Transformation of Sepiolite upon Alkali Activation: Implications for Textural, Catalytic and Sorptive Properties.

Activation of natural sepiolite by means of grinding in a planetary mill followed by wet NaOH activation was studied for the purpose of endowing the product with enhanced basicity for potential catalytic/sorptive applications. Synthesized solids were characterized with X-ray powder diffraction (XRD), N2 adsorption/desorption, scanning electron microscopy (SEM), energy dispersive (EDX), atomic absorption (AAS), Fourier-transform infrared (FTIR) and 29Si magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopies. Surface basicity was determined by titration with benzoic acid. Grinding changed the pathway of sepiolite phase transformation upon NaOH treatment. The as-received sepiolite evolved to Na-sepiolite (loughlinite) with a micropore system blocked by nanocrystalline Mg(OH)2, while ground samples yielded magnesium silicate hydrate phase (MSH), with well-developed microporous texture. In unmilled sepiolite desilication involved preferential leaching of Si from the center of the structural ribbons, while in ground samples additional loss of Si from ribbon-ribbon corner linkages was observed. In all cases treatment with NaOH led to enhancement of surface basicity. Synthesized materials were tested as catalysts in a base-catalyzed aldol self-condensation of acetone and oxidation of cyclohexanone to ε-caprolactone, as well as CO2 sorbents. Catalytic trends depended not only on samples’ basicity, but also on texture and phase composition of the catalysts. Grinding combined with alkali activation proved a simple and effective method for boosting CO2-sorption capacity of sepiolite to the level comparable to amine-functionalized, acid-activated sepiolite sorbents.

Alkali Activated Paste and Concrete Based on of Biomass Bottom Ash with Phosphogypsum

There is a growing interest in the development of new cementitious binders for building construction activities. In this study, biomass bottom ash (BBA) was used as aluminosilicate precursor and phosphogypsum (PG) was used as a calcium source. The mixtures of BBA and PG were activated with the sodium hydroxide solution or the mixture of sodium hydroxide solution and sodium silicate hydrate solution. Alkali activated binders were investigated using X-ray powder diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM) test methods. The compressive strength of hardened paste and fine-grained concrete was also evaluated. After 28 days, the highest compressive strength reached 30.0 MPa—when the BBA was substituted with 15% PG and activated with NaOH solution—which is 14 MPa more than control sample. In addition, BBA fine-grained concrete samples based on BBA with 15% PG substitute activated with NaOH/Na2SiO3 solution showed higher compressive strength compered to when NaOH activator was used −15.4 MPa and 12.9 MPa respectfully. The NaOH/Na2SiO3 activator solution resulted reduced open porosity, so potentially the fine-grained concrete resistance to freeze and thaw increased.

Durability of Fly Ash Based Geopolymer Concrete against Chloride and Sulphuric Acid Attack

The aim of this study was to replace Portland cement with fly ash-based geopolymer as precursors, to serve as a binder after reacting with NaOH and Na2SiO3 activators. The test object existed in the form of a cube of size 50 x 50 x 50 mm. The mortar was treated for 28 days and then immersed in a sulfate solution at similar interval using the wet-dry cycle and non-cycle methods. The compressive strength of the geopolymer mortar was estimated as 45.90 MPa before immersion. Therefore, 35.79 MPa, 41.09 MPa, as well as 37.85 MPa were reported after submersion in the respective solutions of 5% H2SO4, Na2SO4, and NaCl, using wet-dry cycle. Based on the non-cycle approach, the resulting strength was 37.36 MPa, 43.05 MPa and 39.52 MPa correspondingly.

Musa Acuminata Banana Bunch-Based Activated Carbon for Adsorption of Cu(II) Ions in Aqueous Solution: Kinetic and Isotherm Studies

Activated carbon prepared from Musa Acuminata banana bunch (AC-MABB) was proposed in this study. The active sites and morphology structure of three types of the AC-MABB were analysed using FTIR and SEM, respectively. The effect of independent variables namely contact time, Cu(II) ions concentration in solution, NaOH activator concentration, initial pH and temperature on adsorption capacity of the AC-MABB were investigated through batch mode experiments. The Cu(II) ions adsorbed onto the AC-MABB showed excellent fitting to the pseudo second-order adsorption kinetic with a correlation coefficient value of 0.999. Meanwhile it followed Langmuir isotherm with coefficient value of 0.981 and 0.991 at 27 and 57 oC, respectively. The optimum adsorption condition for 1 g of the AC-MABB was observed to be under 0.4 M NaOH activation atmosphere and, stirred at initial pH of 5 with a speed of 100-rpm and a pressure of 1 atm. The maximum Cu(II) ions adsorption capacity based on Langmuir was identified approximately equal to 40.322 and 46.082 mg/g at 27 and 57 oC, respectively.

Highly porous cordierite ceramics from engineered basic activation of metakaolin/talc aqueous suspensions

The cellular structure, in alkali activated metakaolin-based suspensions, foamed by intensive mechanical stirring, is stabilised by the viscosity increase caused by gelation, in a condition of ‘inorganic gel casting’. The approach is so flexibile that it may be applied to mixtures embedding fillers, such as reactive γ-Al2O3 powders, playing a fundamental role upon ceramic conversion. The present study is dedicated to highly porous cordierite foams, obtained including talc as further component, and applying a heat treatment at 1200−1250 °C, in air. A key intermediate step is represented by the removal of Na+ ions from ‘green’ foams, by ion exchange in ammonium nitrate solution (24 h), before ceramization. Direct ceramization is also feasible, if the gelation is achieved by reaction with tetra-methyl-ammonium hydroxide, instead of NaOH. The new gels are effective in yielding phase-pure cordierite, otherwise feasible, with NaOH activation, by means of much longer ion exchange treatment (120 h).

The Characterization of Oyster Shell (Crassostrea gigas) as Adsorbent in The Removal of Cr(VI) Ions. A Study of NaOH and H2SO4 Activation Effect

Abstract : Oyster shell as one of the highest bio-waste in Alue Naga Aceh Besar District, Indonesia, was used as an adsorbent to remove a heavy metal Cr (VI) ion. The study was started by calcinating oyster shells at a high temperature of 800 ºC for 3 hours. The effect of various acid (H2SO4) and base (NaOH) activator was studied using characterization and adsorption experiments. The characterization obtained the sample activated by 10% NaOH (Na10-ACT) and 10% H2SO4 (H10-ACT) had the highest surface area which had 14.23 m2/g, 10.77 m2/g, respectively. Furthermore, the adsorption experiments confirmed the highest surface area by showing the highest Cr (IV) ion removal of 57.66%, 70.7%, respectively. The further investigation using X-ray fluorescence (XRF) determined that the Na10-ACT adsorbent has a better composition compared to the H10-ACT due to its high purities.Abstrak : Cangkang tiram sebagai salah satu bio-limbah padat di Desa Alue Naga Kabupaten Aceh Besar, digunakan sebagai adsorben untuk menghilangkan ion logam berat Cr (IV). Penelitian ini diawali dengan mengkalsinasi cangkang tiram pada temperatur tinggi 800ºC selama tiga jam. Pengaruh penambahan aktivator asam (H2SO4) dan basa (NaOH) juga dipelajari melalui karakterisasi dan pengujian adsorpsi. Hasil karakterisasi menunjukkan sampel yang diaktivasi dengan 10% NaOH (Na10-ACT) dan 10% H2SO4 (H10-ACT) memiliki luas permukaan tertinggi yaitu 14,23 m2/g, 10,77 m2/g, masing-masing. Lebih lanjut, pengujian adsorpsi juga mendukung luas permukaan yang tinggi dengan menghilangkan ion Cr (IV) sebesar 57,66%, 70,7%, masing-masing. Investigasi melalui analisa XRF menyimpulkan bahwa Na10-ACT memiliki komposisi yang lebih baik dibanding H10-ACT karena memiliki kemurnian yang tinggi.

New insight into the phase transformation of sepiolite upon alkali activation: Impact on composition, structure, texture, and catalytic/sorptive properties

Wet NaOH activation of natural sepiolite was studied for the purpose of endowing the material with enhanced basicity for potential catalytic/sorptive applications. A series of synthesized solids were characterized with X-ray powder diffraction (XRD), scanning and transmission electron microscopy (SEM/TEM), X-ray fluorescence (XRF), atomic absorption spectroscopy (AAS), N2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and 29Si magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR). Surface basicity was determined by titration with benzoic acid. The study led to the major reinterpretation of the existing knowledge on the sepiolite phase transformation to its sodium form (loughlinite). Activation with NaOH involved significant desilication of sepiolite, while the loss of Mg from the solid was prevented due to the intracrystalline preciptation of amorphous Mg(OH)2. Formation of Mg(OH)2 affected the material composition, hindered the access of nitrogen molecules to the micropore system, and enhanced the product basicity. For the first time the Si sites at the centre of structural ribbons were identified as part of the silicate framework most susceptible to leaching upon alkaline treatment. Although the NaOH treated product had the structure of loughlinite, it was in fact a composite of desilicated loughlinite and amorphous Mg(OH)2. The materials were tested as catalysts in aldol self condensation of acetone and oxidation of cyclohexanone to ε-caprolactone, and as CO2 sorbents.

Hierarchical porous carbon derived from jujube fruits as sustainable and ultrahigh capacitance material for advanced supercapacitors

Herein, we propose a new highly porous natural carbon material from renewable and inexpensive jujube fruits as a carbon source applied in supercapacitors. The combination of pre-carbonization and chemical activation approaches is employed to product hierarchical porous carbon from natural jujube fruits. The specific surface area of the prepared porous carbon is increased from 85.4 to 1135 m2 g−1 after the completion of NaOH activation at an optimized condition, which is beneficial to enhancing electrochemical performance of supercapacitors. A 3-electrode configuration was utilized to explore the electrochemical ability of porous carbon in 6 M KOH electrolyte. The acquired results demonstrate that porous carbon displays the specific capacitance of 587, 460 and 324 F g−1 at 0.1, 1 and 100 A g−1, respectively, which is confirmed by its admirable capacitance and rate behaviors. The porous carbon also shows a wonderful durability with a capacitance retention of 92.2% after 130,000 cycles at 50 A g−1. Moreover, the assembled symmetrical coin-like supercapacitors with wide potential window of 2.5 V in 1 M Et4NBF4/AN organic electrolyte offer a high energy density of 23.7 Wh kg−1 at 0.629 kW kg−1 with remaining 94% capacitance over 10,000 cycles at 30 A g−1, indicating its practical application prospect. As a result, the present study proves the natural jujube fruits is a promising sustainable carbon source for making more economical and efficient electrode material of high performance supercapacitors.

Chemical Activation of Forage Grass-Derived Biochar for Treatment of Aqueous Antibiotic Sulfamethoxazole.

Chemically activated forage Bermudagrass-derived biochar (A-BC) was produced, characterized, and utilized for adsorption of sulfamethoxazole (SMX) in water for the first time. After NaOH activation, A-BC showed a higher surface area (1991.59 m2/g) and maximum adsorption capacity for SMX (425 mg SMX/g BC) than those of various biochars and commercial activated carbons. The detailed analysis for adsorption of SMX onto A-BC indicated the efficient sorption of SMX through π–π EDA and hydrophobic and hydrogen bond interactions. Additionally, the adsorption of SMX on A-BC was limited by pore and liquid film diffusions. The SMX adsorption on A-BC was found to be endothermic and spontaneous from thermodynamic studies. Furthermore, the highly efficient regeneration of SMX-saturated A-BC over multiple cycles was achieved by NaOH-driven desorption, indicating that the adsorption of SMX onto A-BC would have high potential for cost-effective solution for elimination of SMX from water.

Modification of calcium-rich biochar by loading Si/Mn binary oxide after NaOH activation and its adsorption mechanisms for removal of Cu(II) from aqueous solution

A novel modified calcium-rich biochar by loading Si/Mn binary oxide after NaOH activation (A-Si/Mn-CRBC) was successfully synthesized at 800 °C to enhance the removal of Cu(II) from aqueous solution. The composition and structure of calcium-rich biochars before and after modification were characterized by SEM + EDS, FTIR, XRD and BET. The effect of adsorbent dosage and initial pH on the adsorption behavior of Cu(II) by A-Si/Mn-CRBC was investigated by batch adsorption experiments. The results showed that activation of NaOH before Si/Mn binary oxide loading greatly influenced properties of the materials. It was beneficial to promote smoother surface morphology and more uniform loading of Si/Mn oxide particles in crystalline state. The removal rate of A-Si/Mn-CRBC for Cu(II) with an initial concentration of 50 mg/L was nearly 100 % under the conditions of dosage of 1 g/L and pH = 3–6, and the acidic of the solution could be neutralized during the adsorption process. Kinetics and isotherms studies demonstrated that Cu(II) adsorption onto A-Si/Mn-CRBC was well described by pseudo-second order model and Langmuir model, indicating that monolayer chemisorption was dominant. Langmuir maximum adsorption capacity of A-Si/Mn-CRBC for Cu(II) was 141.76 mg/g. The Weber-Morris model indicated that intra-particle diffusion was the rate-limiting step for the adsorption of high Cu(II) concentration. Thermodynamic analysis confirmed that the adsorption process was spontaneous and endothermic. Adsorption mechanism was ascribed to surface complexation, precipitation, ion exchange and pore-filling. Above all, A-Si/Mn-CRBC is a promising adsorbent for the treatment of acidic heavy metals wastewater.

Preparation of Activated Carbon from Tea Waste by NaOH Activation as A Supercapacitor Material

Karbon aktif dari ampas teh telah disintesis dan telah diuji sebagai elektroda superkapasitor. Pembuatan karbon aktif berdasarkan variasi rasio massa karbon dan aktivator NaOH yaitu 1:4, 1;5 % b/b yang diberi kode AC-4 dan AC-5. Sintesis elektroda karbon aktif di awali dengan proses pra-karbonisasi dan dilanjutkan dengan proses aktivasi kimia. Sampel di karbonisasi pada suhu 800 oC dengan laju kenaikan 50C/menit dalam kondisi gas inert (N2). Karbon aktif ampas teh dikarakterisasi dengan SAA (Surface Area Assessment). Sifat elektrokimia dan kinerja elektroda karbon aktif yang disintesis diukur menggunakan metode voltametri siklik dalam larutan elektrolit H2SO4 1M. Elektroda karbon aktif menunjukkan kapasitansi spesifik tertinggi pada sampel AC-4 yaitu 67 F/g dengan scan rate 1 mV/s dan luas permukaan spesifik 473 m2/g. Mengingat sifat elekrokimia yang menarik tersebut, dan banyaknya ampas teh yang mudah ditemukan disekitar kita maka elektroda karbon aktif ini berpotensi untuk bahan pembuatan superkapasitor elektrokimia skala besar di masa depan.Activated carbon from tea waste has been synthesized and has been tested as a supercapacitor electrode. Making activated carbon based on variations in the ratio of carbon mass and activator NaOH that is 1: 4, 1; 5%wt coded AC-4 and AC-5. Synthesis of activated carbon electrodes begins with the pre-carbonization process and is followed by a chemical activation process. Samples are carbonized at 800 oC with a rate of increase of 50C / min under inert gas (N2) conditions. Activated carbon of tea waste is characterized by SAA (Surface Area Assessment). The electrochemical properties and performance of the activated carbon electrode were measured using the cyclic voltammetry method in a H2SO41 M electrolyte solution. The activated carbon electrode showed the highspecific capacitance in the AC-4 sample of 67 F / g with a scan rate of 1 mV / s and surface area Specifically 473 m2 / g. Considering these interesting electrochemical properties, and the abundance of tea dregs that are easily found around us, this activated carbon electrode has the potential to be a material for making large-scale electrochemical supercapacitors in the future.Keywords:Limbah ampas teh, Aktivator, Kapasitansi spesifik, NaOH, Supekapasitor