Key Engineering Materials Vol. 840

Abstract: Alkylbenzene sulfonates (ABS) is used widely in many industrial and commercial products as surfactants. However, their appearance could cause side effects when released to the environment without treatment. Adsorption method using porous carbon is one of the effective methods to reduce its presence in nature. The aim of this research is to investigate the characters and performances of new type of porous carbon of Jaranan wood carbon (Lannea coromandelica) for ABS removal. Commercial carbon from coconut shell was also used as a comparison. Porous carbons were characterized using scanning electron microscopy SEM and N₂-sorption analyzer. From characterizations, Jaranan wood carbon obtained a higher specific surface area (ca. 1080 m² g^‒1) than the commercial one (ca. 974 m² g^‒1). In the ABS removal test, a lower temperature adsorption is more favorable. The performance of Jaranan wood carbon is comparable to that of commercial porous carbon with uptake capacity up to 3036 mg g^‒1 carbon at 30 °C.

Abstract: Adsorption of Au(III) and Cu(II) by mangosteen rind adsorbent had been carried out. Mangosteen rind has several functional groups including –OH phenolics, ‒C=C‒ aromatics, and ethers. Dried mangosteen rind which was obtained from maceration was used to determine Point of Zero Charge (PZC). The most effective pH adsorption was determined by mixing adsorbent with Au(III) or Cu(II) solutions with various pH. The adsorption capacity was affected by the interaction between adsorbent and adsorbate. The solid adsorbent before and after interaction was characterized by FTIR, XRD, and microphotography. The PZC pH value of adsorbent was 3.7 while the optimum pH for Au(III) and Cu(II) were at pH 2 and pH 5, respectively. The adsorption capacity (q_max) value was 333.33 mg/g by following the Langmuir isotherm equation. The crystalline structure of adsorbent was analyzed using XRD and gave 4 peaks characteristics of gold metal on 2ϴ = 38º, 44º, 64º, and 77º after adsorption which indicated the reduction of Au(III) ions into Au(0).

Abstract: The mangosteen rind has O‒H, C=C aromatics, and ethers functional groups, its performance for Au adsorption become an interesting research to both environment and economic purpose. In this study, waste mangosteen rind as eco-friendly adsorbent had been used for Au(III) adsorption. Initiate by maceration for pre-treatment of biosorbent, the mangosteen rind’s perfomance was revealed. Crystalline structure of mangosteen rind was analyzed by X-ray diffraction, while after interaction with Au(III) ions gave three characteristic peaks indicated Au(III) reduction into Au(0). The adsorption followed isotherm Langmuir model and afforded spontaneous reaction that evidenced by enhancement of ∆G° by increasing of temperature (–1.7 at 30 °C to –8.4 at 60 °C). The value of ∆H° and ∆S° were 71.1 kJ mol^–1 and 238.5 J mol^–1 K^–1, respectively.

Abstract: Research on the adsorption of Cd (II) ion in dithizone-immobilized natural bentonite has been carried out. The aims of this research were focused on the preparation of dithizone-immobilized natural bentonite (BA-D) as adsorbent and desorption experiment of Cd(II) ion. The BA-D was prepared by adding dithizone (dissolved in toluene) into the activated natural bentonite. The adsorbents were characterized by FTIR and X-Ray Diffraction (XRD). This research showed that adsorption capacities of BA-A and BA-D were 1.70×10^‒5 and 2.77×10^‒5 mol g^‒1 (46% of increasing). According to desorption experiment, interaction between activated natural bentonite and Cd(II) ionwere performed by electrostatic interaction, formation of hydrogen bond and complex formation.

Abstract: In this study the performance of biocoagulant based on protein (Moringa oleifera, Vigna sinensi) and tannin (Colocasie esculenta) was compared with Poly Alumunium Chloride (PAC) as a chemical coagulant have been evaluated using a synthetic kaolinite-turbid water which referred to water sample. The effectiveness of biocoagulants dosage were evaluated by turbidity removal (%), total dissolved solid TDS and electrical conductivity (EC). The results showed that the turbidity removal of water sample achieved as much as 94.4% and 87.0% for Moringa oleifera and Vigna sinensi, but low turbidity removal occurred when using Colocasia esculenta as much as 26.4%. High results of turbidity removal showed when using PAC as coagulant at different dosages as a comparison. The decreasing of TDS and EC in the water sample did not much influenced by the coagulants except for Vigna sinensi.

Abstract: The glutaraldehyde (GA)-crosslinked carboxymethyl cellulose (CMC)-polyvinyl alcohol (PVA) film had been synthesized and used as a methylene blue adsorbent. The films were prepared using a solution casting technique and characterized using FTIR spectrophotometer, SEM. Adsorption studies include pH, contact time, methylene blue initial concentration. Furthermore, the desorption study of films was carried out using NaCl, HCl and distilled water. The results of FTIR characterization showed similarities between the spectra of CMC-PVA-GA films with their component materials. The SEM image of CMC-PVA-GA films showed a non-porous surface. In the adsorption study, GA-crosslinked CMC-PVA films (1:2 w/w) exhibited the largest adsorption capacity of methylene blue at optimum conditions for adsorption at pH 7, contact time 200 min, methylene blue concentration of 200 mg L^–1 which was 194 mg g^–1. Methylene blue adsorption kinetic followed the pseudo second-order kinetic model and the Langmuir adsorption isotherm model. The desorption studies show that adsorption takes place through an ion exchange mechanism.

Abstract: The magnetic adsorbent of Fe₃O₄@SiO₂ nanoparticle is modified with an amine group for recovery electroplating industrial waste, which contains Cu²⁺ ion. The magnetic nanoparticles (MNPs) were prepared by the coprecipitation method under sonication and were coated with SiO₂ by acid hydrolysis of sodium citrate under N₂ purging. The nanoparticles were prepared by a coating of silica onto the magnetite nanoparticles via controlled hydrolysis of tetraethyl orthosilicate (TEOS). TEM images suggest that the products have a spherical shape with a particle size of about 20 nm in diameter, and the silica-coated magnetite has a core-shell structure. The Cu²⁺ ion adsorption by magnetic nanoparticles follows the Langmuir isotherm model with a maximum adsorption capacity of 51.04 mg/g at pH 3. The copper ion adsorption by modified MNPs provides easy access to the separation for both the preparation and recovery.

Abstract: The adsorption of Cu (II) ions onto selective adsorbent of coal fly ash from Sugar Factory Madukismo, Yogyakarta, Indonesia modified with dithizone has been investigated in batch mode. Some parameters influencing immobilization of dithizone and adsorption of Cu (II) were optimized including an effect of pH, contact time and initial concentration of Cu (II) ions. The FT-IR and XRD analytical results show that the surface of coal fly ash can be modified by immobilization of selective organic ligand towards Cu (II) ions. The optimum conditions for adsorption of Cu (II) are achieved at pH 5, the optimum mass of DICFA and ACFA for copper adsorption were 0.2 g. Kinetics adsorption for copper ions follows pseudo-second-order kinetics with optimum adsorption contact time 60 min for DICFA and ACFA. Isotherms adsorption for Cu ion follow the Langmuir isotherms with chemisorption process and optimum concentration of Cu ion adsorption of 70 mg.L^-1 for DICFA and ACFA.

Abstract: Adsorption of Pb(II) ions onto selective adsorbent of dithizone-immobilized coal fly ash (DCFA) from Holcim, Cilacap, Indonesia has been investigated in batch experiments. Prepared coal fly ash (CFA) modified by immobilization of dithizone previously were characterized by FT-IR and XRD. Several parameters influencing the adsorption of Pb(II) ions such as effect of pH, adsorbent dosage, contact time and initial concentration of ions on the efficiency of the adsorption were studied. The optimum condition of Pb(II) adsorption was found at pH 5, adsorbent dosage 0.1 g, contact time 60 min and initial Pb(II) ions concentration of 60 mg L^–1. The adsorption kinetics of Pb(II) ions on DCFA was found to follow a pseudo-second-order kinetic model. The adsorption isotherm data were fitted to the Langmuir model. Kinetics and adsorption isotherm studies suggest that the capacity and affinity of the DCFA in adsorbing Pb(II) ions is significantly improved compared to those of non-immobilized activated coal fly ash (ACFA).