Chandra Wahyu Purnomo

Utilization of bagasse fly ash for carbon–zeolite composite preparation

Bagasse fly ash (BFA), a solid waste from sugar cane industries, contains significant amount of carbon as well as silica. The coarse particles with high carbon content can be separated and further activated to produce BFA-based activated carbon, while silica content can be extracted from fine BFA particles to be used for zeolite crystallization. The zeolite crystal may be grown on a suitable solid surface to create a zeolitic composite. In this study, silicate extract from fine BFA particles were combined with pretreated carbon rich coarse BFA particles in a hydrothermal crystallization process to produce particular carbon–zeolite composites. The carbon rich particles could be subjected to any necessary activation or surface treatment before being used in the composite preparation. Meanwhile, a simple method based on thermogravimetry is proposed to evaluate the zeolite particles distribution on the carbon surface. Furthermore, the composite ability for treating mixed organic and inorganic pollutants in aqueous solution has been investigated.

Fixed‐Bed Adsorption Study of Metal Ions on Bagasse Fly Ash (BFA)

Bagasse fly ash (BFA) has become a prospective low cost adsorbent preference for remediating wastewater containing many types of contaminant from organic compounds to toxic metal ions. The abundant availability and its unique characteristics such as large surface area and mesoporous pore size become the major reasons for utilizing BFA as adsorbents. In this paper, the continuous adsorption of Cr(VI), Cu(II) and Ni(II) into fixed bed column of bagasse fly ash (BFA) at room temperature were conducted. The experimental data are represented by breakthrough curves. Fundamental constants which govern the rate of adsorption, such as effective diffusivity of metal ions, have estimated by fitting the data with a breakthrough curve model. The effective diffusivity can be used to predict breakthrough curves in any other adsorption conditions. Meanwhile, the intensive material characterizations have been conducted before the adsorption experiments which successfully reveal the material uniqueness.

Effect of temperature and biomass-water ratio to yield and product characteristics of hydrothermal treatment of biomass

Hydrothemal treatment is a thermochemical process that converts biomass into a coal-like materials called hydrochar by applying elevated temperature to biomass in a suspension with water under saturated pressure for a certain time. With this conversion process, easy to handle fuel with well-defined properties can be created from biomass residues, even with high moisture content. In this research, the effects of temperature (200-330°C) and biomass to water ratio (5%-20%) at initial pressure of 1.0 MPa to hydrothermal treatment of biomass (in the form of sawdust) were examined. All samples were then characterized in terms of yield, proximate analysis, calorific value,and changes in functional groups by FTIR. Approximately 52-69% of the original material was recovered as hydrochar. The gross calorific value ranged from 5472-7032 cal/g compared 5180 cal/g in the raw material. Fixed carbon ranged from 26.035-wt% compared with 26.269 wt% in the raw material.

Lithium recovery from spent Li-ion batteries using coconut shell activated carbon

Lithium is one of scarce natural resources in the world that need to be preserve. One of the way in preserving the resource is by recovery the rich source of the lithium such as in the spent batteries. It is necessary to develop a recovery method which is efficient and low-cost to be able to recover the lithium in an economic scale. In this study, low-cost activated carbon (AC) from coconut shell charcoal was prepared by chemical and physical activation methods and tested for Li removal from Co, Mn, and Ni ions in semi-continuous columns adsorption experiments. The maximum surface area is 365 m2/g with the total pore volume is 0.148 cm3/g that can be produced by physical activation at 800 °C. In the same activation temperature, activation using KOH has larger ratio of micropore volume than physical activation. Then, the adsorption capacity and selectivity of metal ions were investigated. A very low adsorption capacity of AC for Li ions in batch adsorption mode provides an advantage in column applications for separating Li from other metal ions. The AC sample with chemical activation provided better separation than the samples with physical activation in the column adsorption method. During a certain period of early adsorption (lag time), solution collected from the column outlet was found to be rich in Li due to the fast travel time of this light element, while the other heavier metal ions were mostly retained in the AC bed. The maximum lag time is 97.3 min with AC by KOH activation at 750 °C.

The Effects of Binder on the Release of Nutrient from Matrix-Based Slow Release Fertilizer

Bagasse Fly Ash (BFA) a solid waste from sugar cane industry was used as a matrix for preparing Slow Release Fertilizer (SRF). The matrix is a mixture of the BFA with a specific binder i.e. starch and molasses. Then the matrix was mixed with diluted commercial urea fertilizer in an elevated temperature for increasing the solubility of the urea. The effect of the binder and urea-matrix composition are obvious in changing the pattern of release of the nitrogen content from the matrix during 30 days leaching test. The SRF pellets using molasses tend to have faster release rate than the pellet with starch binder. Then, for the pellets with equal amount of matrix and urea (50:50) the release profiles has two sharp increase during the first 5 days and after 15 days, while for the higher urea composition (70:30), the profile only has one sharp release in the beginning followed by a very slow steady release until the end of the test.