Norhashimah Morad

Magnetic nanoparticle (Fe3O4) impregnated onto tea waste for the removal of nickel(II) from aqueous solution

The removal of Ni(II) from aqueous solution by magnetic nanoparticles prepared and impregnated onto tea waste (Fe(3)O(4)-TW) from agriculture biomass was investigated. Magnetic nanoparticles (Fe(3)O(4)) were prepared by chemical precipitation of a Fe(2+) and Fe(3+) salts from aqueous solution by ammonia solution. These magnetic nanoparticles of the adsorbent Fe(3)O(4) were characterized by surface area (BET), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infrared Spectroscopy (FT-IR). The effects of various parameters, such as contact time, pH, concentration, adsorbent dosage and temperature were studied. The kinetics followed is first order in nature, and the value of rate constant was found to be 1.90×10(-2) min(-1) at 100 mg L(-1) and 303 K. Removal efficiency decreases from 99 to 87% by increasing the concentration of Ni(II) in solution from 50 to 100 mg L(-1). It was found that the adsorption of Ni(II) increases by increasing temperature from 303 to 323 K and the process is endothermic in nature. The adsorption isotherm data were fitted to Langmuir and Freundlich equation, and the Langmuir adsorption capacity, Q°, was found to be (38.3)mgg(-1). The results also revealed that nanoparticle impregnated onto tea waste from agriculture biomass, can be an attractive option for metal removal from industrial effluent.

Genetic algorithms in integrated process planning and scheduling

Process planning and scheduling are actually interrelated and should be solved simultaneously. Most integrated process planning and scheduling methods only consider the time aspects of the alternative machines when constructing schedules. The initial part of this paper describes a genetic algorithm (GA) based algorithm that only considers the time aspect of the alternative machines. The scope of consideration is then further extended to include the processing capabilities of alternative machines, with different tolerance limits and processing costs. In the proposed method based on GAs, the processing capabilities of the machines, including processing costs as well as number of rejects produced in alternative machine are considered simultaneously with the scheduling of jobs. The formulation is based on multi-objective weighted-sums optimization, which are to minimize makespan, to minimize total rejects produced and to minimize the total cost of production. A comparison is done w ith the traditional sequential method and the multi-objective genetic algorithm (MOGA) approach, based on the Pareto optimal concept.

Characterization of biopolymeric flocculant (pectin) and organic synthetic flocculant (PAM): A comparative study on treatment and optimization in kaolin suspension

Polyacrylamide (PAM), a commonly used organic synthetic flocculant, is known to have high reduction in turbidity treatment. However, PAM is not readily degradable. In this paper, pectin as a biopolymeric flocculant is used. The objectives are (i) to determine the characteristics of both flocculants (ii) to optimize the treatment processes of both flocculants in synthetic turbid waste water. The results obtained indicated that pectin has a lower average molecular weight at 1.63 x 10(5) and PAM at 6.00 x 10(7). However, the thermal degradation results showed that the onset temperature for pectin is at 165.58 degrees C, while the highest onset temperature obtained for PAM is at 235.39 degrees C. The optimum treatment conditions for the biopolymeric flocculant for flocculating activity was at pH 3, cation concentration at 0.55 mM, and pectin concentration at 3 mg/L. In contrast, PAM was at pH 4, cation concentration >0.05 mM and PAM concentration between 13 and 30 mg/L.

Adsorption Studies of Methylene Blue and Malachite Green From Aqueous Solutions by Pretreated Lignocellulosic Materials

Lignocellullosic materials have been used as low-cost adsorbents for the removal of methylene blue (MB) and malachite green (MG) dyes from aqueous solutions. The organic compounds in the adsorbents that contribute to chemical oxygen demand (COD) have been removed through pretreatment of the adsorbents. The percentage of color removal and COD reduction of both MB and MG dyes were found relatively close in values. The adsorption process followed the Langmuir isotherm as well as the Freundlich isotherm and pseudo-second order kinetic model. The process was found to be endothermic in nature.

Treatment of Terasil Red R Dye Wastewater using H2O2/pyridine/Cu(II) System

The H(2)O(2)/pyridine/Cu(II) advanced oxidation system was used to assess the efficiency of the treatment of a 1 g L(-1) Terasil Red R dye solution. This system was found to be capable in reducing the concentration of chemical oxygen demand (COD) of the dye solution up to 90%, and achieving 99% in decolorization at the optimal concentration of 5.5mM H(2)O(2), 38 mM pyridine and 1.68 mM Cu(II). The final concentration of COD was recorded at 117 mg L(-1) and color point at 320 PtCo. Full 2(4) factorial design and the response surface methodology using central composite design (CCD) were utilized in the screening and optimization of this study. Treatment efficiency was found to be pH independent. The amount of sludge generation was in the range of 100-175 mg L(-1) and the sludge produced at the optimal concentration was 170 mg L(-1).

Degradation of cationic and anionic dyes in coagulation–flocculation process using bi-functionalized silica hybrid with aluminum-ferric as auxiliary agent

Cationic dye (methylene blue) and anionic dye (methyl orange) degradation in the coagulation process was demonstrated. The key material was a natural coagulant–laterite soil dominated by a silica component, while aluminum-ferric ions acted as an auxiliary agent in the degradation process. Charge neutralization, electrical double layer compression and sweeping flocculation were the mechanisms in the decolorization reaction. These results provided a new insight into effective dye degradation using a new class of natural coagulant–natural resources (laterite soil). The complex molecular structure of methylene blue and methyl orange was degraded into smaller hydrocarbon forms, accompanied by the formation of silsesquioxane. The silsesquioxane was the final product of degradation with promising flocculation and low volume sludge. Lastly, a comparison of the aluminum-based coagulant and a laterite soil natural coagulant shows a clear vision of the performance for both types of coagulant.

Synthesis and Characterization of Hydrophobically Modified Cationic Polyacrylamide with Low Concentration of Cationic Monomer

Hydrophobically modified cationic polyacrylamides were synthesized via free radical solution copolymerization using ammonium persulphate/sodium hydrogen sulphite as the redox initiator. Epichlorohydrin, acrylamide and trialkylamine were used to synthesize the hydrophobic cationic monomer 3-acrylamido-2-hydroxypropyltriakylammonium chloride (AHPTAAC) in which the trialkyl group was trihexylamine (AHPTHAC), trioctylamine (AHPTOAC) and tridodecylamine (AHPTDAC). Low concentration (1–6 mol%) of cationic monomer from each group were copolymerized with acrylamide to obtain hydrophobically modified cationic polyacrylamide. Results show that the intrinsic viscosity and molecular weight of the copolymers decreases with the concentration of the hydrophobic cationic group, whereas charge density indicates the reverse behaviour. Fourier Transform Infrared (FTIR) and Transmission Electron Microscopy (TEM) were also carried out to elucidate the structure of the copolymer.

Synthesis and Characterization of Hydrophobically Modified Cationic Acrylamide Copolymer

Abstract Hydrophobically modified cationic acrylamide copolymers were synthesized by free radical solution copolymerization using potassium persulfate as the initiator. Epichlorohydrin, acrylamide, and tridodecylamine were used to synthesize the hydrophobically modified cationic monomer, i.e., 3-acrylamido-2-hydroxypropyltridodecylammonium chloride (AHPTDAC), which was then copolymerized with acrylamide. The intrinsic viscosity, molecular weight, and charge density of the copolymers depend on the ratio of AHPTDAC and acrylamide used. Fourier transform-infrared (FT-IR) and transmission electron microscopy (TEM) were used to elucidate the structure of the copolymer. The solid copolymer is insoluble in water but only swells in the aqueous medium.

Physicochemical and Rheological Properties of Novel Magnesium Salt-Polyacrylamide Composite Polymers

Two series of novel inorganic-organic composite polymers have been prepared through physical blending of magnesium chloride and magnesium hydroxide respectively with polyacrylamide aqueous solution. The physicochemical properties of the magnesium salt-polyacrylamide composite polymers were tuned by varying the ratio between the magnesium salt (e.g., magnesium chloride and magnesium hydroxide) and polyacrylamide. Characterizations of magnesium salt-polyacrylamide composite polymers were carried out via FTIR and TEM. Parameters such as solution conductivity and viscosity were also taken into account to characterize the physicochemical properties of the composite polymer aqueous solutions. Magnesium chloride-polyacrylamide (MCPAM) composite polymer aqueous solutions have a higher conductivity compared to magnesium hydroxide-polyacrylamide (MHPAM) composite polymer aqueous solutions. The viscosities of the MHPAM composite polymer aqueous solutions were found higher than MCPAM composite polymer aqueous solutions. The rheological properties of the composite polymer aqueous solutions were investigated using steady-state flow and oscillatory frequency sweep within the linear viscoelastic region. Shear-thinning effect was observed for both composite polymer systems when the shear rate increases. In oscillatory frequency sweep tests, both composite polymer systems show that the viscoelastic behaviors depend strongly on the magnesium salt concentrations. Viscous behavior was found to be dominant for both composite polymer systems.

Removal of Rhodamine B Dye Using Activated Carbon Prepared from Palm Kernel Shell and Coated with Iron Oxide Nanoparticles

The efficacy of activated carbon prepared from Palm Kernel Shell (PKSAC) from agriculture biomass and coated with magnetic nanoparticle (Fe3O4) in the removal of Rhodamine B dye was investigated. Adsorption experiments were carried out at various initial pH, adsorbent dosage, initial dye concentration, particle size, and temperature. Kinetic analyses were conducted using pseudo first order, pseudo second order and intra particle diffusion models. However, the regression results showed that the adsorption kinetics was represented more accurately by the pseudo second order model. The pseudo second order kinetic constant obtained was 1.7 × 10−4 min−1 at 323 K when 200 mg L−1 dye concentration was used. The equilibrium data were well described by both Langmuir and Freundlich isotherm models. The Langmuir adsorption capacity was 625 mgg−1. The rate of adsorption improved with increasing temperature and the process was endothermic with ΔH value assessed at 80 kJmol−1. Results obtained reveal that activated carbon prepared from Palm Kernel Shell coated with magnetic nanoparticle from agriculture biomass can be an attractive option for dye removal from industrial effluent.