Activated Carbons Prepared from Oil Palm Shells: Characterisations and Application for Column Separation of Heavy Metals

Wastes from agricultural products are abundant, suitable to be used as precursor for producing activated carbons. These wastes, instead of causing significant disposal problems, can be turned into by-products for industries by utilizing them fur manufacturing activated carbons. Carbonization and activation processes were done in the Tubular Carbolite Furnace. N₂ gas was flowed for the first 3 hours followed by CO₂ gas for the next 1 hour on the precursor at the constant temperature of 500°C. Par the H₃PO₄ impregnation, 30 grams of the palm shells were impregnated with 15 ml ofH3P04 and diluted with 100 ml of distilled water to produce 2.2 M H₃PO₄ solution. For the K₃PO₄, 30 grams of palm shells were impregnated with 9 g of K₃PO₄ and diluted with 100 ml of distilled water to produce 9% w/w K₃PO₄ solution. For the KOH impregnation, 30 grams or palm shells were impregnated with 9 g of KOH and diluted with 100 ml of distilled water to produce 9 % w/w KOH solution

Removal of Malachite Green from Aqueous Solution by waste tyre derived activated carbon

Waste rubber tyres were used to prepare activated carbon via destructive distillation method employing a two stage process i.e. carbonization and chemical activation in a tubular furnace. Carbonization was done at 500°C for 1 h followed by impregnation of char with NaOH. Activation was done in a horizontal tube furnace via CO2 activation. Two variables and three parameters i.e. impregnation ratio between NaOH and char (1:1 and 3:1), activation temperature (700°C and 900°C), and activation time (60 min and 180 min) were studied and its effects on percentage yield, and malachite green (MG) dye removal were compared and presented in this paper. IR spectra of all samples a number of bands at 1710, 1620, and 1054 cm–1 –1026 cm–1 which proved the presence of carboxylic, carbonyl, and some acids, alcohols, ether and ester groups on the surface of carbon prepared. Activated carbon, AC6, which was prepared at ratio 3:1 and heated at 900°C for 60 min preparation was selected due to high surface area (313.17 m2/g) and removed about 97.43% of MG dye after 60 minutes. AC6 was best fitted to the Freundlich isotherm indicating multilayer adsorption while the adsorption kinetic followed pseudosecond order kinetics. The maximum monolayer adsorption was 128.21 mg/g

Remediation of anionic dye simulated wastewater using TiO2 as a photocatalyst under various light irradiation wavelength

Heterogeneous photocatalytic process employing UV/TiO2 batch photo-reactor system was demonstrated to be effective in the photodegradation of C.I. Reactive Black 5 anionic dye. Various artificial lamps (UV-A, UV-B, UV-C and solar irradiation) were used to activate the TiO2-P25 Degussa photocatalyst. UV-C was found to be the best in degrading RB5 with 100% efficiency at the 25th min with an R2 = 0.9786 according to the first order reaction kinetic model. The effectiveness of UV-C is due to the shorter penetration capability with higher energy photon, so there was more electron-hole pairs available for the target compound. Photodegradation with UV-B was also similarly effective while UV-A and solar irradiations were least effective. Increasing the initial dye concentration reduced the degradation rate due to the inner photon filtering effect by the dye molecules. Since RB5 is anionic dye, by increasing the pH of the system, the degradation rate was reduced to 99.65% in 1 h at pH10. This is due to the electrostatic attraction between the dye molecules and the negatively charged TiO2 particles. Photocatalytic degradation was found to be affected by the pollutant concentration and solution pH which were explored and described in detail in this article

Photodegradation of indigo dye using TiO2 and TiO2/zeolite system

Photodegradation of indigo dye in aqueous solution using anatase TiO2 and TiO2/zeolite composite photocatalyst were studied. The composite photocatalysts were prepared by using sol-gel method. Calcination sol-gel was performed in a muffle furnace at 450 ºC for 4 h. The photocatalysts were characterized using SEM and XRD. 0.4 g of photocatalysts were used to degrade 500 mL of indigo dye giving a constant catalyst loading of 0.8 g/L in varying indigo dye concentration of between 10-20 mg/L. The results showed that the photocatalytic behaviour of TiO2/zeolite composite sample was better as the degree of degradation for TiO2/zeolite was higher compared to the neat TiO2 sample. The percentage degradation achieved by using TiO2/zeolite in 10 and 20 mg/L were 58.6 and 75.0 % respectively. In addition, the degradation process followed the first-order reaction kinetics where the rate constant, k, for the degradation of indigo dye solution was in the range of 0.1207-0.2669 h-1 (not presented). This work demonstrates that the sol-gel method was successful in preparing an effective TiO2/zeolite composite photocatalyst

Application of modified red mud in environmentally-benign applications: a review paper

Red mud (RM) is a waste product that results from bauxite refining via the Bayer process. Its disposal remains an issue which raises significant environmental concerns, particularly if disposed on land or water bodies. Much research has been done on the use of red mud for environmentally-benign applications such as wastewater treatment, catalysis, the production of construction materials and glass ceramics, and for the recovery of metals. This paper reviews the current efforts made in the utilization of red mud as a valuable industrial by-product, which in turn should minimize its harmful impact on the environment. This detailed review compiles and highlights a variety of novel applications of modified red mud as a coagulant, an adsorbent for wastewater treatment, as well as, its use in catalytic processes and in building materials. The physico-chemical properties of red mud can be tuned by a range of treatment methods include acidification, neutralization and heat treatment. As revealed from the literature reviewed, modifications on red mud for the removal of various types of contaminants have shown promising results. However, further amendment and modifications on red mud are needed to utilize this industrial waste in many other industrial applications

Removal of sulphur and nitrogen compounds from model fuel by adsorption of modified activated carbon

This study aimed to achieve the highest percentage removal of dibenzothiophene (DBT), quinoline (QUI), and indole (IND) adsorbed by double-impregnated modified activated carbon (MAC). Modification of commercial activated carbon (AC) by sulphuric acid (H2SO4) of 15%, 30%, 45%, 60%, and 75% w/v followed by subsequent 1 zinc chloride (ZnCl2): 1 AC impregnation ratio and activated at 500 oC in a muffle furnace under self-generated atmosphere for an hour. The determination of optimized MAC was identified through the highest removal rate of DBT, QUI, and IND from adsorption experiments which were analysed using an ultraviolet-visible (UV-Vis) spectrophotometer. It was found that DBT and IND showed a removal high percentage of up to 86.23% and 82.77% respectively by using 75% H2SO4 with ZnCl2 MAC. Meanwhile, QUI favoured 30% H2SO4 with ZnCl2 MAC with a removal percentage of 33.17% which was still higher than unmodified AC. Physical and chemical properties such as the morphological structure, elemental analysis, porosity, pore size, surface functional group, percentage yield, pH, bulk density, content, ash content, and iodine number were studied for the optimized MAC. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy and Fourier transform infrared spectroscopy (FTIR) were used to characterize the MAC. Both MACs showed high percentage yields of 72.08% and 71.13% for 30% and 75% H2SO4 and ZnCl2 MAC respectively. Meanwhile, the pH was between the ranges of 5.36-5.53 for both MACs. Bulk densities were also favourable while the moisture and ash content were within acceptable limits. Iodine numbers for 30% and 75% H2SO4 and ZnCl2 MAC were 857 and 861 mg/g respectively, hence indicating that the MAC achieved high porosity and good adsorption performance. Langmuir, Freundlich, and Temkin adsorption isotherm models as well as pseudo-first order (PFO) and pseudo-second order (PSO) kinetic models were considered for understanding the adsorption mechanisms. The study revealed that DBT, QUI, and IND removal processes, followed the Langmuir adsorption isotherm model with correlation coefficients, R2 of 0.9905, 0.9791, and 0.9964 respectively. Moreover, the adsorption kinetic data of DBT, QUI, and IND provided a better fitting to the PSO kinetic model with R2 of 0.9992, 0.9987, and 0.9998 respectively. According to the Langmuir isotherm model and PSO kinetic model, the adsorption mechanisms of DBT QUI and IND were chemisorbed under monolayer formations

Operating parameters and synergistic effects of combining ultrasound and ultraviolet irradiation in the degradation of 2,4,6-trichlorophenol

The sonophotodegradation of 2,4,6-trichlorophenol (TCP) in a homogeneous aqueous system was investigated. The effectiveness of sonolytic, photolytic and sonophotolytic oxidation processes in the degradation of aqueous solutions of TCP was investigated by applying ultrasonic waves or ultraviolet radiation or a combination of these two techniques. The optimum operating parameters for the horn-type sonicator and the UV-A lamp were determined along with the effect of temperature on the TCP degradation. It was found that an increase in acoustic intensity and UV lamp intensity was proportional to an increased efficiency of the sonolytic and photolytic degradation of TCP. However, an increase in the solution temperature caused the TCP to evaporate resulting in the first-order kinetic rate showing the presence of a synergistic effect at temperatures between 10 °C and 20 °C, an additive effect at a temperature of 30 °C and an antagonistic effect at temperatures of 40 °C and higher

Preparation and characterization of activated carbon from Typha orientalis leaves

Background In this study, activated carbon (AC) was prepared from Typha orientalis or commonly known as cattail leaves using physical and chemical activation phosphoric acid (H3PO4), as dehydrating agent. A two-stage process was used, i.e., semi-carbonization stage at 200 °C for 15 min as first stage followed by second stage activation, at 500 °C for 45 min. The precursor material with the impregnated agent was exposed straight away to semi-carbonization and activation temperature using a laboratory scale muffle furnace (Carbolite RHF 1500, England) under static condition in a self-generated atmosphere. Results The best condition in AC production was based on chemical activation which is AC2 with 2 M of H3PO4. AC2 has the highest removal efficiency, 97.4 % in 4 ppm concentration of Pb(II) and percentage yield of 62.73 % could be reached. The pH of the AC was controlled in the range 5–6. From Fourier transform infrared spectroscopy, functional groups such as hydroxyl group, lactone group, and carboxyl group were obtained. These were clearly illustrated by scanning electron microscopy micrographs that porous structure was progressively developed with sponge-like structure. Conclusions The Pb(II) adsorption results were best fitted in the Langmuir isotherm for equilibrium data while the adsorption kinetic fitted to the pseudo-second order model. The maximum Brunauer, Emmett and Teller surface area of the best produced AC was found to be around 1,238 m2/g. The maximum adsorption capacity was found to be 7.95 mg/g