Optimization on Na and Ca bentonite activation using response surface method for increasing selectivity of stevioside in stevia extract

The demand for stevia extract consumption as an alternative sweetener that contains stevioside with zero-calorie is increasing. However, dark color and high tannin content from stevia leaf extract causes a disturbing aftertaste and reduces interest in consumption. Therefore, the purification process is a mandatory step to be done. Several studies on purification methods show the best approach by adsorption using bentonite. However, natural bentonite has limited adsorption capacity and low selectivity. An activation with acid and high temperature is expected to increase the adsorption capacity of color and its selectivity on maintaining the stevioside at the extract. This study aimed to obtain the optimum acid concentration and temperature for the activation using the Response Surface Method (RSM) experimental design and its application to the purification of stevia leaf extract. Based on the parameter of methylene blue number, the most optimum concentration of H2SO4 used for activation was 0.17 N for both natural bentonite. The heating temperature was 358°C for Na-bentonite and 481°C for Ca bentonite. The maximum adsorption capacities of activated Na and Ca-bentonite were increased from 15.65 and 38.23 mg g-1 to 197.72 and 169.52 mg g-1, respectively. The best adsorbent used for purification is Ca-activated, which increased extract clarification up to 81.37% at 655 nm and 86.64% at 410 nm compared to natural Ca bentonite. It also reduced tannin up to 97.46% and was more selective to recover 50.64% stevia content in the solution, which was higher than other previously reported studies.

Chemical Activation of Garcinia mangostana Mangosteen Shell with Acid-Base for Hexavalent Chromium Adsorption

This study investigates the potential for using mangosteen shell which is an agricultural waste to chemically activate using potassium hydroxide (KOH) or phosphoric acid (H3PO4) and then carbonized for 120 min at 673 K, to adsorb hexavalent chromium (Cr6+) from solution. The high iodine number and methylene blue number on the base-activation as a good adsorbent that a high surface area of this activated carbonaceous material is effective in removing Cr6+, with adsorption increasing with temperature, adsorption time, and initial feed concentration. With decreasing solution pH, the maximum of Cr6+ adsorption capacity and removal at a pH of 2.0 was achieved.

Fabrication of open type carbonizer for the preparation of activated carbon from rice husk

Activated carbon has been prepared from rice husk using laboratory fabricated open type carbonizer. The raw rice husk powder was named as RRH whereas chemically activated rice husk was named as CARH. Both samples were characterized by methylene blue number (MBN), iodine number (IN) and surface area. The MBN and IN of RRH was found to be 83 mg/g and 415 mg/g whereas CARH was 99 mg/g and 716 mg/g respectively which indicate the presence of mesoporosity and microporosity of the samples. The surface area of RRH was found to be 206 m2/g while CARH was found to be 531 m2/g. XRD analysis showed that the prepared materials were amorphous with some crystalline state while FTIR spectra showed the presence of different functional groups such as hydroxyl, carbonyl, Si-O-Si bond and aromatic group on the material. The adsorption properties of prepared samples were studied by using Langmuir and Freundlich isotherm models. Langmuir adsorption isotherm model was found to be best fitted. It showed that prepared materials have homogenous surface with monolayer type of adsorption. The maximum monolayer coverage (Qm) for RRH was found to be 55 mg/g and for CARH 143 mg/g. Thus, results revealed that laboratory fabricated low cost open type carbonizer is suitable for the preparation of activated carbon. BIBECHANA 18 (2021) 10-18

Preparation of Activated Carbons based Balanites Aegyptiaca Shells by Chemical Activation: Optimization Conditions Using the Methodology of Experimental Design

The optimization conditions of preparation of activated carbons based Balanites aegytiaca shells by chemical activation was investigated. The effects of three parameters of preparation namely, the activation temperature (600-800 °C), impregnation ratio (1:4-3:8) and residence time (60-120 min) were thoroughly studied on the activated carbon yield (Yld, Y1), iodine number (ION,Y2) and methylene blue number (MBN, Y3) using the Methodology of Experimental Design (MED). The analysis of variance (ANOVA) under the experimental domain revealed that, the activation temperature of 800 °C, residence time of 02hrs and impregnation ratio of 1:2 were the optimum conditions of preparation leading to activated carbon yield of 23.0%, iodine number of 889.0 mg/g and methylene blue number of 9.7 mg/g. The polynomial equation showed that the three parameters were both synergetic and antagonistic on the responses retained. The higher values of iodine numbers obtained alongside the experimental matrix is an indication that the activated carbons so prepared were mainly microporous.

Synthesis and Characterization of Sugarcane Bagasse Based Activated Carbon: Effect of Impregnation Ratio of ZnCl2

Series of activated carbons (ACs) have been prepared from Sugarcane bagasse powder by ZnCl2 activation at various impregnation ratios of ZnCl2 to Sugarcane bagasse powder of 0.25:1, 0.5:1, 1:1 and 2:1 by weight. Characteristics of the activated carbons (ACs) were determined by iodine number, methylene blue number, surface area, scanning electron microscopy (SEM) and x-ray diffraction. Iodine number (IN) indicated that, microporosity of the AC were increased with increasing impregnation ratio ZnCl2 to Sugarcane bagasse upto 1:1 then started to decrease. However, mesoporosity as well as surface area was increased progressively. The maximum value of iodine number (868 mg/g) was achieved in the AC prepared at impregnation ratio of ZnCl2 to sugarcane bagasse 1:1. SEM micrographs also show the presence of well developed pores on its surface of AC-1. The broad peaks in the XRD patterns indicated that, all the ACs is amorphous materials. From results, it is concluded that ZnCl2 concentration used in impregnation is effective for development of porosity and surface area of the AC prepared from Sugarcane bagasse.

Synthesis and Characterization of Active Biocarbon Material for Use in Cosmetics and Personal Care Products

Consumer’s preference towards organic material enriched nature based green products in the cosmetics and personal care industry have intensified over the years. This paper shares the synthesis and characterization of an active organic biocarbon material derived from carbonized powdered coconut shell by bicarbonate cured activation for use in charcoal-based cosmetic and personal care products. The optimum conditions for activation was observed at 800 °C, run for 180 min, with a bicarbonate impregnation ratio of 1:3. Experimental design followed Box-Behnken approach. The increase in iodine (757.30 mg/g) and methylene blue number (111.00 mg/g) are indicative of a highly porous biocarbon material that reflects its excellent adsorption capability. Suitability of the biocarbon material for application in charcoal-based cosmetic formulation mixture was supported through proximate, texture, and color analysis. Overall material characteristics are beneficial for effective adsorbent and exfoliant functions in cleansing, detoxifying, and scrubbing.

Determination of Methylene blue Number to Characterize the Lapsi Based Activated carbon Prepared by Chemical Carbonization

Determination of Methylene blue Number of the activated carbons prepared by Chemical Carbonization from waste material, seed stone of Lapsi has been studied. Methylene blue Number has been determined by single point method using batch adsorption method. Acids like concentrated sulphuric acid and a mixture of concentrated sulphuric acid and concentrated nitric acid have been used to prepare activated carbon. The activated carbon prepared by using a mixture of concentrated sulphuric acid and concentrated nitric acid has been found to have higher methylene blue number than the activated carbon prepared by using concentrated sulphuric acid. The activated carbons thus prepared can be used as effective adsorbents for the remediation of pollutants from water.

Preparation of Activated Carbon from (Punica granatum .sp) Wood by Chemical Treatment Using Potassium Hydroxide.

In the present study, activated carbons were prepared from Punicagranatum .sp, using potassium hydroxide as activating agent. Punicagranatum .sp activated carbon(PGAC) was characterization using methylene blue number, iodine number and some physical properties such as humidity, ash content and density. The perfect measurement for this study was the proportion of (1:2.5)(wood : KOH) to give 560mg for iodine number and 67mg for methylene blue number which are good result. http://dx.doi.org/10.25130/tjps.24.2019.107

Comparative Study on the Adsorption Capacity of Activated Carbon Prepared from Lapsi Seed Stone and Betel nut using Phosphoric Acid

This paper presents the comparative study on the adsorption capacity of activated carbons prepared from Lapsi (Choerospondias axillaris) seed stone and Betel (Areca catechu) nut. Activated carbons (ACs) were prepared from Lapsi seed stone (LSS) and Betel Nut (BN) by chemical activation with H3PO4 (in the ratio of 1:1 by weight) at 400°C. The pore structure of activated carbons was determined by iodine number and methylene blue number. Surface morphology of ACs was studied by scanning electron microscopy (SEM). Surface functional groups were analyzed by Fourier Transform Infra Red Spectroscopy (FTIR). As indicated by TGA analysis, the appropriate temperature required for carbonization was 400 ºC. Betel nut AC showed high iodine number and methylene number of 888 mg/gm and 369 mg/gm respectively. SEM micrographs of Betel nut AC show the presence of well developed pores on its surface. FTIR result indicated that both ACs contain −OH, >C=O groups as oxygen containing surface functional groups. Based on the result, the AC prepared from betel nut by activation with H3PO4 is comparable with commercial activated carbon and could be used as potential adsorbent for removal of pollutants from water and waste water.Journal of the Institute of Engineering, 2017, 13(1): 153-159

Preparation and Characterization of Activated Carbon from Waste Sawdust from Saw Mill

Activated carbon was prepared in laboratory using waste sawdust powder of Shorea robusta (Sal) from saw mill by chemically activated Na2CO3 followed by carbonization technique. Thus prepared activated carbon was characterized by Iodine Number (IN) and Methylene Blue Number (MBN). Iodine number was found to be 534.6 mg/g whereas MBN was found to be 196.08 mg/g which indicated the presence of micropores as well as mesopores in the prepared material. This was also exposed by SEM image. Specific surface area was measured by BET method and was found to be 10.01 m2/g. Then phase state of samples was determined by X-ray diffraction (XRD), which indicated the amorphous nature of the prepared material. The development of surface functionality due to activation was examined by Fourier Transform Infrared Spectroscopy (FTIR) which showed the presence of oxygenated functional groups such as ether, diketone, lactone, phenol on the material. These functional groups are considered to be electrochemically active and contribute to the capacitance of electrical double layer capacitance (EDLC). Further, electrochemical characterization of prepared material was carried out by conductivity test and cyclic voltammetry. The cyclic voltametric curve showed symmetric rectangular shape indicating electrical double layer capacitive behavior. Journal of Institute of Science and TechnologyVolume 22, Issue 2, January 2018, Page: 103-108