A.A. Ahmad

Organic dye adsorption on activated carbon derived from solid waste

Activated carbon was prepared through a chemical activation of bamboo waste precursor (BMAC) using phosphoric acid as the activating agent at 500°C for 2 h. Batch adsorption studies were carried out for the adsorption of C.I. Reactive Black 5 (RB5) onto the BMAC. The effect of various experimental parameters such as initial dye concentration (50–500 mg/L), contact time (0–32 h), pH (2–12), and temperature (30–50°C) were investigated. Equilibrium data were found to be very well represented by the Freundlich isotherm and a pseudo-second-order model was found to explain the kinetics of RB5 adsorption more effectively. The mechanism of the adsorption process was determined by the intraparticle diffusion model. Thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°), standard free energy (ΔG°), and activation energy were determined. The results indicated that BMAC is a suitable adsorbent material for adsorption of reactive dye from aqueous solutions.

Modeling of disperse dye adsorption onto bamboo-based activated carbon in fixed-bed column

ABSTRACTThe adsorption of I.C. Disperse Orange 30 (DO30) onto bamboo-based activated carbon (BMAC) was investigated in a fixed-bed column. The experiments were conducted to study the effect of important parameters: bed depth (4–8 cm), flow rate (10–30 mL/min), and inlet DO30 concentrations (50–200 mg/L). The experimental results showed that the breakthrough time decreased with increased flow rate and inlet concentration and it decreased bed height. The highest bed capacity of 39.97 mg/g was obtained to use 100 mg/L inlet DO30 concentration, 8 cm bed height, and 10 mL/min flow rate. Adams–Bohart, bed depth service time (BDST), Thomas and Yoon–Nelson models were applied to predict the breakthrough point using linear regression and to determine the characteristic parameters of the column. Thomas model prediction was in a very good agreement with the experimental results at all the process parameters. The study indicates that it is very suitable for BMAC column design.

Release and recovery of phosphorus from wastewater treatment sludge via struvite precipitation

AbstractThe release and the recovery of phosphorus (P) from aerobically digested wastewater, sludge during thermal treatment and the solid–liquid separation by struvite precipitation were investigated. The effects of pH, temperature, and heating time on the liberated phosphate from solid phase to liquid phase were determined. After the wastewater treatment, sludge was thermally treated at a temperature over 100°C, no microbial activities were observed over a period of 24 h. The maximum total phosphorus release of 48.9 mg/L (93.6%) was observed at pH 2 ± 3, 170°C in 80 min. The results showed that the optimum pH values that released phosphate ions from the solid phase to the solution were noted at the range of 2–4. The scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) indicated that struvite precipitation is unshaped and nonuniform crystal formed. The surface composition of the precipitates contains high amount of O, P, Mg, and trace of C, Cl. The Fourier transform infrared spectr...

Color and COD reduction from cotton textile processing wastewater by activated carbon derived from solid waste in column mode

Abstract Rattan-activated carbon was evaluated for color reduction and chemical oxygen demand (COD) of a cotton textile mill wastewater in a fixed-bed adsorption column. The maximum adsorption capacities of color and COD were 100.15 Pt/Co and 73.23 mg/L, respectively, at 10 mL/min flow rate and 80 mm bed height. Kinetic models, Adams–Bohart, Thomas and Yoon–Nelson were applied to experimental data to predict the breakthrough curves using linear regression. The Thomas and Yoon–Nelson models were found suitable for the description of the breakthrough curve while the Adams–Bohart model was only used to predict the initial part of the dynamic process. The results of this study indicated the applicability of fixed-bed column for reduction of color and COD from textile mill wastewater.

Preparation and characterization of activated carbons derived from bio-solid: a review

AbstractPreparation of activated carbons from bio-solid is a promising way to dispose bio-solid as well as to produce a low-cost adsorbent for pollutant removal. Various physical and chemical processes are in use for the activation of the activated carbon derived from bio-solid (ACBS). Both physical and chemical characterizations provide fundamental knowledge for its potential application for pollutants removal. The literature illustrates that KOH, the chemical activation procedure is found to be the most effective technique for producing high BET surface area ACBS, with areas in excess of 1,882 m2/g being reported. In this review, the results reveal that the ACBS is comparable with commercially activated carbons.

Adsorption of 4-nitrophenol on palm oil fuel ash activated by amino silane coupling agent

Abstract Adsorption of 4-nitrophenol on palm oil fuel ash activated by amino silane coupling agent was investigated. Experiments were carried out at 30°C as function of contact time, initial concentration (2500–4500 mgl−1) and pH (1–7.4). The equilibrium adsorption data of 4-nitrophenol on activated palm ash were analyzed by Langmuir Freundlich and Temkin models. The results indicated that the Langmuir model provides the best correlation of the experimental data. The maximum adsorption capacity of the activated palm oil fuel ash was determined with the Langmuir equation and found to be 1000 mg g−1 adsorbent at 30oC. Adsorption kinetics data were modeled using the pseudo-first-order, pseudo-second-order and intra-particle diffusion equations. It was shown that pseudo-second-order kinetic equation could best describe the adsorption kinetics. The results obtained in this work indicate that activated palm oil fuel ash is suitable as adsorbent material for adsorption of 4-nitrophenol from aqueous solutions.