Biosorption of Pb(II) and Fe(III) from Aqueous Solutions Using Oil Palm Biomasses as Adsorbents

Biosorption of Pb(II) and Fe(III) from Aqueous Solutions Using Oil Palm Biomasses as Adsorbents
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  Biosorption of Pb(II) and Fe(III) from Aqueous SolutionsUsing Oil Palm Biomasses as Adsorbents Shabnam Khosravihaftkhany  &  Norhashimah Morad  & Tjoon Tow Teng  &  Ahmad Zuhairi Abdullah  &  Ismail Norli Received: 27 August 2012 /Accepted: 15 January 2013 /Published online: 8 February 2013 # Springer Science+Business Media Dordrecht 2013 Abstract  The removal of lead (II) and iron (III) fromaqueous solutions using empty fruit bunch (EFB), oil palm leaves (OPL), oil palm frond (OPF), and oil palm bark (OPB) as biosorbents was investigated. The bio-sorbents were characterized through scanning electronmicroscopy, Brunauer   –  Emmett   –  Teller analysis, andFourier transform infrared spectroscopy. Variablessuch as pH (2  –  12), biosorbent particle size (200  –  1,400  μ  m), adsorbent dosage (0.25  –  1.75 g/l), andagitation time (5  –  80 min) were investigated. The suit-able pH range, particle size, adsorbent dosage, andagitation time for the removal of both metals were 5to 6, 200  μ  m, 1 g/l, and 40 min, respectively. Under optimum conditions, OPB showed the highest adsorp-tion efficiency of 80 % and 78 % for lead and iron,respectively. The adsorption equilibrium data werefitted to three adsorption isotherm models. TheLangmuir isotherm showed the best result for bothmetals. The kinetics of the biosorption process wasanalyzed using pseudo-first-order and pseudo-second-order models. The latter showed a better fit for bothmetals. OPB biomass introduced the lowest chemicaloxygen demand into the treated solution, with anaverage amount of 32.9 mg/l. Keywords  Biosorption.Lead.Iron.Oilpalm biomasses.Isotherms.Kineticmodel 1 Introduction The discharge of industrial effluents to the water resour-ces is one of the major environmental problems that need to be properly addressed. Heavy metals such asiron, copper, lead, zinc and nickel are among the most common inorganic pollutants found in industrial waste-water (Al-Rub 2006; Reddy et al. 2011). Heavy metals are toxic pollutants that can accumulate in living tissuesand cause various diseases and disorders (Witek-Krowiak et al. 2011). The content of heavy metals inindustrial wastewater is a worldwide environmental problem (Amarasinghe and Williams 2007). Heavy metals can be removed from wastewater using a variety of technologies depending on water quality expectation, economic concerns, and local leg-islation. Waste stabilization ponds (Shpiner et al.2009), chlorination and thermal treatment (Nowak et al. 2010), electrochemical-switchable polymer film(Le et al. 2009), chitosan and chitosan derivatives (Miretzky and Cirelli 2009), flocculation/precipitation (Bratskaya et al. 2009), and adsorption methods (Mansour et al. 2011; Nasef and Yahaya  2009; Water Air Soil Pollut (2013) 224:1455DOI 10.1007/s11270-013-1455-yS. Khosravihaftkhany :  N. Morad ( * ) : T. T. Teng : I. NorliSchool of Industrial Technology, Universiti Sains Malaysia,11800 Penang, Malaysia e-mail: nhashima@usm.myA. Z. AbdullahSchool of Chemical Engineering, Universiti Sains Malaysia,14300 Nibong Tebal, Penang, Malaysia   Selvam et al. 2008; Tofighy and Mohammadi 2011) are some of the highly reported separation methods.Biosorption has been used for the removal of heavymetals.It is a passive bindingprocess betweenmetals andnonliving microorganisms/other biomass types that canefficiently collect heavy metals (Lesmana et al. 2009). This process is a cost-effective and efficient alternativemethod for water and wastewater treatment (Bhatnagar et al. 2010). Biosorbents are obtained from naturally occur-ring and agricultural waste materials that are cheaper,renewable, and abundantly available (Bhatnagar et al.2010). Palm trees are abundant, particularly in Southeast AsiancountrieslikeIndonesia,Malaysia,andThailand.In2008,morethan44,800km 2 oflanduseinMalaysiawereunder oil palm cultivation (Chiew et al. 2011). The oil  palm industry generates many types of biomass, such asmesocarp fiber, shell, empty fruit bunch (EFB), oil palmfrond(OPF),andoilpalmbark(OPB)(Yacobetal.2006). Oilpalmfruitfiber(AbiaandAsuquo2008),oilpalmleaf  powder  (Sulaiman et al. 2010), oil palm kernel fiber  (Ofomaja  2010), EFB-activated carbon (Wahi et al. 2009), and oil palm ash (Chu and Hashim 2002) are among the adsorbents investigated for the removal of different heavy metals from aqueous solutions.Littleinformationisknownaboutthe removalofironusing agricultural wastes such as oil palm biomasses.Therefore, studies investigating their use in the removalof heavy metal ions from aqueous solutions are highlyimportant.This studyaimstoinvestigatethepotentialof oil palm tree biomasses for the adsorption of iron andlead ions from aqueous solutions. Biomasses should becharacterized fully because the physical and chemicalcharacteristics of biosorbents could affect the sorption process. This study focused on EFB, oil palm leaves(OPL), OPF, and OPB as biosorbents. The effects of equilibrium pH, particle size, adsorbent dosage, andagitation time on the removal of heavy metals fromaqueous solutions were also investigated. The adsorp-tion equilibrium data were analyzed using different ad-sorptionisothermmodels, and the kineticsof adsorptionfor the two metals was determined. 2 Methodology 2.1 Biomass PreparationOPB, OPF, and OPL were obtained from oil palm plantationsinNibongTebal,Penang,Malaysia,whereasEFBwasobtainedfromUnitedPalm Oil MillinNibongTebal, Penang, Malaysia. After reducing in size, these biomasses were thoroughly washed with boiling dis-tilled water to remove any impurities. Subsequently,they were dried in an oven at 110 °C for 24 h, groundand sieved with five mesh sizes between 200 and1,400 μ  m, and then stored in airtight bottles. No further chemical or physical treatment was performed prior tothe adsorption experiments.2.2 Biomass CharacterizationA scanning electron microscope (SEM Leo Supra 50VP Field emission) was used to characterize the mor- phological characteristics of all the adsorbents. Fourier transform infrared spectroscopy (FTIR-Is10) analysiswas carried out to identify the functional groups re-sponsible for the adsorption in the oil palm biomasses.The ratio between each sample and potassium bromidewas set at approximately 1:100 prior to the compac-tion into thin pellets using a 7-ton force of hydraulic press for 5 min. The specific surface areas of the biomasses were determined based on the Brunauer   –  Emmett   –  Teller (BET) multipoint technique.2.3 Preparation of Metal SolutionSynthetic wastewater solution was prepared by dis-solving analytical grade FeCl 3  (R&M Chemicals;99 %) and Pb(NO 3 ) 2  (Avonchem Ltd.; 99 %) in deion-ized water. The concentration of each metal in thesolution was fixed at 500 mg/l. Sodium hydroxide(1.0 mol/l) and hydrochloric acid (1.0 mol/l) solutionswere used for pH adjustment of the syntheticwastewater.2.4 Adsorption TestsBatch adsorption tests were conducted by mixing the biomass with a 100-m solution of known metal ionconcentration. The sorption experiments were per-formed under different operating conditions. A seriesof experiments was conducted to determine the effectsof pH (2, 4, 6, 8, 10, and 12), adsorbent particle size(mesh sizes between 200 and 1,400  μ  m), adsorbent dosage (0.25, 0.50, 0.75, 1.00, 1.25, 1.50, and1.75 g/l), and agitation time (5, 10, 20, 40, 60, and80 min). At the end of each experiment, the liquidsamples were filtered, and the filtrate was analyzed for  1455, Page 2 of 14 Water Air Soil Pollut (2013) 224:1455  metal ion and chemical oxygen demand (COD) con-tents. In order to obtain the exact amount of heavymetal biosorption, in each experiment, the blank solu-tion was also tested. This was done to exclude theeffect of heavy metal precipitation. The percentageof heavy metal removal from the solution was calcu-lated as follows:% removal ¼  C 0  C i C 0  100  ð 1 Þ where  C  0  is the initial concentration of heavy metalsand  C  i  is the final concentration of heavy metals.Isotherm studies were carried out by varying the initialmetal ion concentration in the solution (10, 20, 50, and100 mg/l for each salt). Based on the mass balancerelationship, the adsorption capacity  q e  (mg/g) after equilibrium was calculated as follows: q e  ¼  C  0  C  i ð Þ  V W   ð 2 Þ where  V   is the volume of the solution (l) and  W   is themass of the biosorbent (g). After all the experiments,the COD test was carried out using a spectrophotom-eter (Hach, USA) following the Standard Method No.5220 D (close reflux, colorimetric method) (APHA et al., 2006). This test was performed to ensure that thesolution is free from secondary pollutants srcinatingfrom the biosorbent material after the treatment pro-cess. At the end of each run, the sample was filteredrapidly, and the metal concentration in the filtrate wasdetermined using a Perkin Elmer (AAnalyst 100)atomic absorption spectrometer (AAS). 3 Results and Discussion 3.1 Biomass Characterization 3.1.1 Morphology The SEM micrographs of the biosorbents are shown inFig. 1. All biomasses were an assemblage of fine particles, which did not have regular or fixed shapeand size. The particles were of various dimensions andcontained a large number of steps and kinks on theexternal surface, with broken edges. The surface of the biomaterial had some cavities throughout the surfaceof the adsorbents, indicating that this material pos-sessed good characteristics as natural adsorbents for heavy metal removal. The SEM of OPB in Fig. 1a shows a compact structure with cracks which could bedue to higher surface area compared to other oil palm biomasses. The BETanalysis also confirmed the high-est surface area of the OPB (Table 1). 3.1.2 FTIR Spectroscopy The FTIR spectra of each biomass before and after adsorption are shown in Fig. 2. The spectra displayedseveral vibrational bands, indicating the complex na-ture of the materials. The broad, intense absorption peaks around 3,410 to 3,450 cm − 1 are indicative of theexistence of bounded  –  OH (Arslanoglu et al. 2008;Jacques et al. 2007). The peaks observed at 2,919 to2,924 cm − 1 can be assigned to the C  –  H group(Arslanoglu et al. 2008; Jacques et al. 2007; Mohan and Gandhimathi 2009), whereas the bands observedat 2,280 to 2,365 cm − 1 are assigned to C ≡ C and C ≡  N(Southichak et al. 2009). The peaks at 1,730 to 1,740 cm − 1 are assigned to a CO stretching of carbox-ylic acid or pectin ester  (Jacques et al. 2007), whereas those at 1,620 to 1,648 cm − 1 are attributed to C=O andC=C bands (Oh et al. 2009; Southichak et al. 2009). The intense band at 1,240 to 1,390 cm − 1 occurs in theregion associated with carboxyl groups  –  COOH (Mata et al. 2009).The spectra of the OPB biomass before and after adsorption are illustrated in Fig. 2a . The bands at 2,921.54 cm − 1 (C  –  H) and 1,629.77 cm − 1 (C=O andC=C) decreased and the bands at 2,360.08 cm − 1 (C ≡ C) and 2,342.01 cm − 1 (C ≡  N) appeared. After bio-sorption, the band at 34,16.92 cm − 1 ( − OH) decreasedin intensity and changed to band 3,417.09 ( − OH)cm − 1 .Figure 2b shows the spectra of OPF biomass beforeand after adsorption. The wave number shifted from1,639.77 to 1,629.33 cm − 1 after OPF loading withsolution. This finding suggests that the C=O andC=C groups played a major role in the adsorption of lead (II) and iron (III) from the aqueous solution. Thewave numbers of 2,360.28 cm − 1 (C ≡ C and C ≡  N),1,736.14 cm − 1 (CO), 1,383.80 cm − 1 (COOH), and1,248.04 cm − 1 (COOH) decreased in intensity.The spectra of EFB are shown in Fig. 2c. The bandsat 2,283.22 cm − 1 (C ≡ C and C ≡  N) and 2,923.08 cm − 1 (C  –  H) completely disappeared after adsorption. Thespectrum of the OPL biomass is shown in Fig. 2d. Thewave numbers of 2,360.14 cm − 1 (C ≡ C and C ≡  N) and Water Air Soil Pollut (2013) 224:1455 Page 3 of 14, 1455  2,921.84 cm − 1 (C  –  H) disappeared after treatment withthe aqueous solution. The wave number of 1,640.44 cm − 1 (C=O and C=C) was divided andshifted into wave numbers of 1,629.06 and1,735.43 cm − 1 (CO stretching of carboxylic acid or  pectin ester). These results show that the C=O andC=C groups have a principal involvement in themechanism of adsorption. 3.1.3 Surface Area Table 1 shows the surface area of the biomasses based on the nitrogen adsorption  –  desorption (mul-tipoint BET) method. OPB had the largest surfacearea (121.5 m 2 /g), whereas OPL had the lowest (41.2 m 2 /g). The surface areas of OPF and EFBwere 63.8 and 53.3 m 2 /g, respectively. No signif-icant differences in pore volume were found be-tween OPF and EFB, with 0.076 and 0.071 cm 3 /g,respectively. OPB had the largest pore volume(0.148 cm 3 /g).The heavy metal removal efficiency of the four  biomasses was in the sequence of OPL < EFB <OPF < OPB, which was also the sequence in termsof surface area. Thus, active surface area plays a major role in the adsorption process investigated in thiswork. Fig. 1  Scanning electron micrographs of the four biosorbents:  a  OPB,  b  OPF,  c  EFB,  d  OPL, magnification: ×1000 Table 1  Characteristics of the unmodified biomassesAdsorbent Surface area (m 2 g − 1 ) Pore volume (cm 3 g − 1 )OPB 121.5 0.148OPF 63.8 0.076EFB 53.3 0.071OPL 41.2 0.0491455, Page 4 of 14 Water Air Soil Pollut (2013) 224:1455  Fig. 2  FTIR analysis of thefour biosorbents before andafter usage:  a  OPB,  b  OPF,  c EFB,  d  OPLWater Air Soil Pollut (2013) 224:1455 Page 5 of 14, 1455
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