PREPARASI DAN KARAKTERISASI KARBON AKTIF DARI ARANG TEMPURUNG KELAPA SERTA APLIKASINYA SEBAGAI ADSORBEN BIRU METILENA; PREPARATION AND CHARACTERIZATION OF ACTIVATED CARBON FROM COCONUT SHELL CHARCOAL AND APPLICATION AS AN ADSORBENT METHYLENE BLUE

Tani, Djefry, Bambang Setiaji

2015 | Tesis | FMIPA

The preparation and characterization of activated carbon from the charcoals which were produced by coconut shell pyrolysis and its application as an adsorbent methylene blue have been conducted. Preparation was conducted using a combination of chemical and physical activation with flowed CO2 gas. Chemical activation is done using KOH activator, H3PO4 and ZnCl2 with varying concentrations of 0.5 to 2.0 M with a range of 0.5 M, variations of immersion time ranging from 12 to 24 hours with a range of 6 hours. Activation of physics carried out at various temperatures of 500 to 800 °C to 100 °C range and variation of the activation time of 30 to 150 minutes with a span of 30 minutes. Meanwhile, the adsorption activity test includes pH, contact time, and the concentration of methylene blue. Kinetics of adsorption kinetics was analyzed using several models, and models of adsorption isotherms to determine the capacity and energy of adsorption. Characterization of activated carbon includes chemical and physical properties which consist of macro analysis by determining the absorption of iodine. Meanwhile, the micro analysis includes: determining the functional group with a Fourier Transform Infra Red (FTIR), the identification of the crystal properties using X-ray diffraction (XRD), specific surface area, total pore volume, and average pore by N2 adsorption according to Brunauer-Emmett-Teller (BET). Morphology of activated carbon with a Scanning Electron Microscope (SEM), the uniformity of the pore with Transmission Electron Microscope (TEM), and the thermal stability was determined using Differential Thermal Analysis-Thermogravimetry Analysis (DTA-TGA). The results of this research showed that the product of an activated carbon as the result of the combination of chemical and physical activation experienced changes of the physicochemical properties from the base material of coconut shell charcoal into activated carbon that has a mesoporous structure. The results show that activated carbon which uses activators such as KOH, H3PO4 and ZnCl2 in optimum condition, namely the activation of the 120 minutes and the temperature is 800°C has the best physical and chemical properties as follows: specific surface area respectively is 451.14; 359.29; and 299,43 m2g-1. Average pore radii of 11.02 to 11.89 ?. Kinetics study results showed that the adsorption capacity of activated carbon to the methylene blue respectively in accordance with the activators are used in succession is an activator KOH according Langmuir isotherm at 52.44 mg g-1, activator H3PO4 according Freundlich isotherm of 0.44 mg g-1, and activators ZnCl2 according Freundlich isotherm at 5.54 mg g-1. Thus activated carbon that has been produced by the combination of of the chemical and physical combination can be used as adsorben. Adsorption kinetics of methylene blue solution by activated carbon as the result of activation with activator KOH, H3PO4 and ZnCl2 at the beginning concentration 50 mgL-1 in a row is a second pseudo order; order two; and a second order with the adsorption rate constant (k) respectively of 0.25 g ?mol-1 min-1; 11,26 mmol-1 min-1 and 384,90 g ?mol-1 min-1.

Kata Kunci : coconut shell; activated carbon; chemical and physical activation; methylene blue.