Papers by Keyword: Pb (II)

Abstract: The development of green adsorbents from natural resources for heavy metals in polluted water is due to their abundance, environmentally friendly, and low cost. The second most abundant natural polymer after cellulose is lignin. However, lignin capability for heavy metal ion adsorption especially Pb (II) is still very low. Therefore, modifications of lignin is needed by adding a new functional group to the lignin such as Mg (OH)₂. It is expected to improve the adsorption ability of lignin to Pb (II). In this research, we used lignin from bagasse as a source. After isolating the lignin molecule, a lignin-Mg (OH)₂ has been synthesized by reflux method forming hydrogen bonds with Mg (OH)₂ which can be seen from the results of characterization using FTIR. The synthesized lignin-Mg (OH)₂ has diameter 300-450 nm with an irregular shape. Adsorption ability of lignin-Mg (OH)₂ to Pb (II) was conducted using an UV-Vis spectrophotometer by the addition of Alizarin Red S (ARS) as complexing agent. The kinetics study of adsorption process was elucidated by pseudo-first-order and pseudo-second-order models. Adsorption process was described by the Freundlich and Langmuir models. The adsorption process of lignin-Mg (OH)₂ to Pb (II) was endothermic and spontaneous in nature. The experimental results show that lignin-Mg (OH)₂ has a greater capability of adsorption to Pb (II) than lignin bagasse. Lignin-Mg (OH)₂ has maximum adsorption capacity to Pb (II) of 40.16 mg/g at 25°C and percent removal up to 96%. Meanwhile, lignin bagasse has a maximum adsorption capacity of 12.85 mg/g at 25°C and a percent removal of 68%.

Abstract: Adsorbents from green and sustainable source are highly desirable for practical applications. In this study, humic acid-like substance extracted from dry horse dung powder and carboxymethyl cellulose (CMC) were adopted to fabricate a composite immobilized on magnetic precipitates of magnetite. The as-prepared adsorbent, denoted as CMC-MHDHA, was analyzed by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission and scanning electron microscopy equipped with energy dispersive X-ray (TEM and SEM-EDX), thermo gravimetric analysis (TGA), and vibration sample magnometer (VSM). Application to the synthetic wastewater of Pb (II) and Rhodamine B (RhB), a high Langmuir monolayer adsorption capacity of 63.38 and 42.78 mg/g was achieved over CMC-MHDHA, respectively. The fabricated adsorbent was also demonstrating quick and easy retraction of pollutant-loaded adsorbent by an external magnet with the magnetic strength of 40.7 emu/g. Based on the estimated free adsorption energy of Dubinin-Radusckevich (D-R) isotherm model, the adsorption interaction of both Pb (II) (9.76 kJ/mol) and RhB (12.39 kJ/mol) with CMC-MHDHA was mainly occurred by ion exchange mechanism. Adsorption rate analysis at the initial adsorbate concentration ranged from 50 to 400 mg/L of both Pb (II) and RhB showed that the rapid adsorption generally occurs in early 20 minutes then slow down and reaches equilibrium after 180 minutes. The Ho (pseudo second order) kinetics model represent appropriately the adsorption of both Pb (II) and RhB onto the adsorbent. The developed adsorbent is also reusable with 72.3% of stability in pH 11. Therefore, the adsorbent of CMC-MHDHA is suggested to be a promising candidate for adsorption applications.

Abstract: The use of agricultural by-products has been widely studied to develop effective and inexpensive adsorbent for heavy metal removal. In this study, sago (M.sagu) fly ash (FA) was chemically modified to afford an operational adsorbent for Pb (II) elimination from water. Chemical modification was carried out via acid-base treatment using NaOH and HCl. The chemically modified fly ash (MFA) was characterized via proximate, surface morphology, and functional groups' surface area analyses. The effects of adsorption parameters, namely, Pb (II) initial concentration, sorbent dosage and contact time on the eradication of Pb (II) by MFA was analyzed in batch experiments with Langmuir and Freundlich isotherms. Optimization of Pb (II) removal by MFA was studied via response surface methodology (RSM) approach. Results revealed that chemical modification has successfully enhanced the adsorptive properties of MFA (BET surface area: 231.4 m²/g, fixed carbon: 55.83%). MFA exhibits better Pb (II) removal efficiency (90.8%) compared to FA (63.6%) at the following adsorption condition: Pb (II) initial concentration (5 ppm), contact time (30 min) and agitation speed (150 rpm). The adsorption of Pb (II) by FA and MFA fitted well with Freundlich isotherm (R²>0.9). RSM study suggested that the optimum Pb (II) removal was 99.4% at the following conditions: Pb (II) initial concentration (20 ppm), contact time (2 h) and sorbent dosage (0.6 g/50 mL). The results concluded the potential optimum operational condition for Pb (II) removal from aqueous environment by MFA as a low cost adsorbent, at larger scale.

Abstract: With rapid industrial development, the water pollution due to industrial wastewater discharge also increases. Wastewater containing heavy metals such as Lead (Pb(II)) has been one of the serious global issues. It is because lead has a high level of toxicity and very harmful to the environment as well as human body even at low level of concentration. One of the emerging methods for removal of Pb(II) from aqueous solution is called biosorption. It is adsorption process using biomass-based adsorbent or can be called biosorbent. One of biomass material that can be used for the biosorbent for removal of Pb(II) is Kapok wood sawdust. In this study, biosorbent based Kapok sawdust has been successfully prepared. The effects of pH and contact time on the adsorption performance of the biosorbent have been studied. The adsorption tests were carried out with variations in pH 4, 5, 6, and 7 and with variations in contact time of 30, 60, and 90 minutes. The amout of Pb(II) adsorbed was analyzed using Atomic Absorption Spectroscopy (AAS). The adsorption test results showed that the equilibrium contact time required for the biosorbent to absorb Pb(II) was 60 minutes, while the pH optimum was achieved at pH = 7. Furthermore, from the adsorption test results, it has also been concluded that the optimum adsorption capacity (q_e) 4.83 mg/g and removal percentage (96.6%) was achieved by Adsorbent A (i.e. Kapok sawdust biosorbent activated with 0.2 M HNO₃).

Abstract: Synthesis of C-2-ethoxycarbonylmethoxyphenyl calix [4] resorcinarene and its application for adsorption of Pb (II) metal cation have been carried out. C-2-ethoxycarbonylmethoxyphenyl calix [4] resorsinarene was produced in three steps i.e (1) esterification of 2-chloro acetic acid, (2) reaction ethyl 2-chloro acetate with salicylaldehide in to yield 2-ethoxycarbonylmethoxy benzaldehyde, and (3) reaction 2-ethoxycarbonylmethoxy benzaldehyde with resorcinol in acidic condition to yield C-2-ethoxycarbonylmethoxyphenyl calix [4] resorcinarene. The prepared compounds were characterized by FTIR, 1H-NMR dan 13C-NMR spectrophotometers. The adsorption kinetic of Pb (II) adsorption in batch followed pseudo 2nd order kinetic model. The isotherm study showed that the adsorption followed Langmuir model.