Norasikin Saman

Application of waste materials as adsorbent for water treatment has obtained special attention owning to their low cost and surface functionality. In this study the waste-treatment sludge (WTS) sludge was selected as based materials and used as adsorbents for dyes and antibiotic adsorption. The adsorbent was prepared by calcination of the washed and dried WTS adsorbent (S105) at 300 °C (S300) and 700 °C (S700). The morphology, elemental composition, functional groups, pH at point zero charged, and cationic exchange capacity were observed and evaluated to understand the adsorption performance capability of the adsorbents. Then, the adsorbents were test for dyes and antibiotic adsorption in aqueous solution. Adsorbent prepared at higher temperature have darker color. The FTIR peaks related to functional groups of organic compounds such as OH and CO were diminished when the WTS was calcined at 700 °C. Value of pHpzc of of S105, S300 and S700 were 5.43, 5.81 and 5.89, respectively. The value of CEC for S700 and S105 however lower than S300. Adsorption performance of WTS adsorbents towards cationic methylene blue (MB), anionic methyl orange (MO) and reactive red-120 was evaluated in aqueous solution. All adsorbents show high adsorption performance towards MO, but lower adsorption performance towards RR was observed. The calcination of WTS results the higher adsorption capacity observed for adsorption of anionic and cationic dyes. The S700 also show better adsorption performance towards OTC and TC. This study indicates that the WTS has a potential application as low-cost adsorbent to remove hazardous substances from aqueous solution.

The aim of this work is to convert agroforestry residue to a novel adsorbent (M-1CTA-SDS-BT) used for adsorptive benzene sequestration from aqueous solution. In this study, the anionic surfactant-coated-cationized banana trunk was synthesized and characterized for batch adsorption of benzene from aqueous solution. The surface morphology, surface chemistry, surface area, and pore properties of the synthesized adsorbents were examined. It was proven that surface cationization successfully increased the benzene adsorption capacity of sodium dodecyl sulfate-coated adsorbents. The Langmuir isotherm model satisfactorily described the equilibrium adsorption data. The maximum benzene adsorption capacity (q_max) of 468.19 μmol/g was attained. The kinetic data followed the pseudo-second-order kinetic model in which the rate-limiting step was proven to be the film diffusion. The batch-adsorbent regeneration results indicated that the M-1CTA-SDS-BT could withstand at least five adsorption/desorption cycles without drastic adsorption capacity reduction. The findings demonstrated the adsorptive potential of agroforestry-based adsorbent as a natural and cheap material for benzene removal from contaminated water.

The preparation of chars and activated carbon as low-cost elemental mercury adsorbents was carried out through the carbonisation of coconut husk (pith and fibre) and the activation of chars with potassium hydroxide (KOH), respectively. The synthesised adsorbents were characterised by using scanning electron microscopy, Fourier transform infrared spectroscopy and nitrogen adsorption/desorption analysis. The elemental mercury removal performance was measured using a conventional flow type packed-bed adsorber. The physical and chemical properties of the adsorbents changed as a result of the carbonisation and activation process, hence affecting on the extent of elemental mercury adsorption. The highest elemental mercury (Hg°) adsorption capacity was obtained for the CP-CHAR (3142.57 µg g⁻¹), which significantly outperformed the pristine and activated carbon adsorbents, as well as higher than some adsorbents reported in the literature.

Lignocellulosic coconut wastes such as pith and fiber, which are abundantly available and cheap, have the potential of being used as low-cost biosorbents for heavy metal ion removal. In this study, pristine (CF-Pristine) and NaOH-treated (CF-NaOH) coconut fibers were used as a biosorbent for Hg(II) removal from an aqueous solution. The coconut fiber biosorbent (CFB) was characterized by scanning electron microscopy (SEM) and Fourier transform-infrared (FTIR) spectroscopy. The Hg(II) sorption capacities obtained for CF-Pristine and CF-NaOH were 144.4 and 135.0 mg/g, respectively. Both the equilibrium and kinetic data of Hg(II) sorption onto CFB followed the Langmuir isotherm model and a pseudo-second-order kinetic model, respectively. A further analysis of the kinetic data suggested that the Hg(II) sorption process was governed by both intraparticle and external mass transfer processes, in which film diffusion was the rate-limiting step. These results demonstrated that both pristine- and alkali-treated coconut wastes could be potential low-cost biosorbent alternatives for the removal of Hg(II) from aqueous solutions, such as water containing Hg(II) produced in the oil and gas industry.

Rasped pith sago residue (RPSR) was used as a biosorbent for inorganic (Hg(II)) and organic (CH₃Hg(I)) mercury removal from aqueous solutions. In biosorbent preparation, the RPSR having particle size range of 0.06–0.10 was washed with deionized water repeatedly to eliminate impurities, dried in an oven at 50°C for two days, followed with drying in a vacuum oven for 3 h. The performance of RPSR as a novel biosorbent for removing mercury was evaluated in batch adsorption. The adsorption of mercury ions was found to highly dependent on the pH of the solutions. The Hg(II) adsorption was high at pH > 4, while the CH₃Hg(I) adsorption was found higher at pH < 5. The higher adsorption capacity for Hg(II) and CH₃Hg(I) was 0.288 and 0.213 mmol/g, respectively. Both mercury adsorptions equilibrium and kinetics were fitted to the Langmuir isotherm model and pseudo‐second‐order kinetic model, respectively. These results indicate the RPSR has a potential to be a low‐cost biosorbent for mercury removal process from aqueous solutions.