Statistical optimization of adsorption processes for removal of 2,4-dichlorophenol by activated carbon derived from oil palm empty fruit bunches

The adsorption capacity of activated carbon produced from oil palm empty fruit bunches through removal of 2,4-dichlorophenol from aqueous solution was carried out in the laboratory. The activated carbon was produced by thermal activation of activation time with 30 min at 800℃. The adsorption process conditions were determined with the statistical optimization followed by central composite design. A developed polynomial model for operating conditions of adsorption process indicated that the optimum conditions for maximum adsorption of phenolic compound were： agitation rate of 100 r/min, contact time of 8 h, initial adsorbate concentration of 250 mg/L and pH 4. Adsorption isotherms were conducted to evaluate biosorption process. Langmuir isotherm was more favorable （R^2=0.93） for removal of 2,4-dichlorophenol by the activated carbon rather than Freundlich isotherm （R^2=0.88）.

Dimensional Stability Properties of Medium Density Fibreboard (MDF) from Treated Oil Palm (Elaeis guineensis) Empty Fruit Bunches (EFB) Fibres

The aim of the study was to investigate the effect of pre-treatments by using sodium hydroxide (NaOH) and acetic acid on oil palm Empty Fruit Bunch (EFB) fibres for the production of Medium Density Fibreboard (MDF). The EFB fibres were treated with chemicals in the concentration range of 0.2%, 0.4%, 0.6% and 0.8% prior to refining. Single-homogenous layer MDF with 12 mm thickness and density of 720 kg/m3 was produced. Urea-Formaldehyde (UF) was applied at 10% loading (based on dry weight of dry fibres) as a binder. The physical properties (Water Absorption (WA) and Thickness Swelling (TS)) of the produced panels were tested according to European Standard, EN 622-5:2006. The results show that types of chemical used had greater effects than concentration on the dimensional stability of the MDF. EFB fibres treated with acetic acid produced MDF with better dimensional stability compared to the MDF NaOH treated fibres. High concentration of NaOH produced poor dimensional stability in the panels.

Activated carbons derived from oil palm empty-fruit bunches: Application to environmental problems

Activated carbons derived from oil palm empty fruit bunches （EFB） were investigated to find the suitability of its application for removal of phenol in aqueous solution through adsorption process, Two types of activation namely; thermal activation at 300, 500 and 800℃and physical activation at 150℃ （boiling treatment） were used for the production of the activated carbons. A control （untreated EFB） was used to compare the adsorption capacity of the activated carbons produced from these processes. The results indicated that the activated carbon derived at the temperature of 800℃ showed maximum absorption capacity in the aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon at 800℃. It was observed that the adsorption capacity was higher at lower values of pH （2-3） and higher value of initial concentration of phenol （200-300 mg/L）. The equilibrium data fitted better with the Freundlich adsorption isotherm compared to the Langmuir. Kinetic studies of phenol adsorption onto activated carbons were also studied to evaluate the adsorption rate. The estimated cost for production of activated carbon from EFB was shown in lower price （USD 0.50/kg of activated carbon） compared the activated carbon from other sources and processes.

Characterization of Formacell Lignin Derived from Black Liquor as a Potential Green Additive for Advanced Biocomposites

Black liquor is obtained as a by-product of the pulping process,which is used to convert biomass into pulp by removing lignin,hemicelluloses and other extractives from wood to free cellulose fibers.Lignin represents a major constituent in black liquor,with quantities varying from 20%to 30%,of which a very low share is used for manufacturing value-added products,while the rest is mainly burned for energy purposes,thus underestimating its great potential as a raw material.Therefore,it is essential to establish new isolation and extraction methods to increase lignin valorization in the development of bio-based chemicals.The aim of this research work was to determine the effect of KOH or ethanol concentration as an isolation agent on lignin yields and the chemical characteristics of lignin isolated from formacell black liquor of oil palm empty fruit bunch(OPEFB).Isolation of lignin was carried out using KOH with various concentrations ranging from 5%to 15%(w/v).Ethanol was also used to precipitate lignin from black liquor at concentrations varying from 5%to 30%(v/v).The results obtained showed that the addition of KOH solution at 12.5%and 15%concentrations resulted in better lignin yield and chemical properties of lignin,i.e.,pH values of 3.86 and 4.27,lignin yield of 12.78%and 14.95%,methoxyl content of 11.33%and 10.13%,and lignin equivalent weights of 476.25 and 427.03,respectively.Due to its phenolic structure and rich functional groups that are favorable for modifications,lignin has the potential to be used as a green additive in the development of advanced biocomposite products in various applications to replace current fossil fuel-based material,ranging from fillers,fire retardants,formaldehyde scavengers,carbon fibers,aerogels,and wood adhesives.

The Use of Molecular-Sieving Materials as Ameliorant for Peat Degradation in the Tropics

Peat utilization for agriculture expansion area is commonly found extensively in tropical region during the last few decades. Most agronomical practices involve drainage resulting decomposition of organic materials and increasing drying. This study was carried out to determine the potential use of molecular-sieving materials (MPMs) as an ameliorant for peat soil targeted for reducing the potential hazard of peat degradation. A clinoptilolite-zeolite, empty fruit bunches of oil palm biochar (EFBOPB), and their combination were studied its characteristics to evaluate the ability in adsorbing water and green-house gas emission. A series of laboratory analyses were conducted to determine physicochemical and mineralogical characteristics of both materials and its combination, including elemental analyses, cation exchange capacity (CEC), pH, ore spaces, water holding capacity (WHC), and adsorption capacity for CO2, NH3, and N2. The study revealed that 100 - 150 mesh size of zeolite possesses higher values of CEC, WHC, and adsorption capacity for CO2, NH3, and N2 compared to EFBOPB, whereas the latter indicated a higher organic-C content and pore spaces. Combination of 75% (w/w) zeolite and 25% (w/w) EFBOPB showed the best composition of these two MPMs to improve WHC of peat and as consequences slowing down the firing process of the peat. Based on the gas adsorption data, it could be assumed that the mixture of MPMs studied could be considered as an effective material to reduce risk of peat from fire potential hazard and retard GHG emission.

Investigation of biomass surface modification using non-thermal plasma treatment

The effects of non-thermal plasma （NTP） treatment on biomass in the form of pulverized palmbased empty fruit bunches （EFB） are investigated. Specifically, this study investigates the effects of NTP treatment on the surface reactivity, morphology, oxygen-to-carbon （O/C） ratio of the EFB at varying treatment times. The surface reactivity is determined by the reaction of antioxidant functional groups or reactive species with 2,2-diphenyl-l-picrylhydrazyl （DPPH）. By measuring the concentration of the DPPH with a spectrophotometer, the change in the amount of antioxidant functional groups can be measured to determine the surface reactivity. The reactions of the various lignin components in the EFB with respect to the NTP treatment are discussed by qualitatively assessing the changes in the Fourier transform infrared （FTIR） spectra. The surface morphology is examined by a scanning electron microscope. To determine the amount of oxygen deposited on the EFB by the air-based NTP treatment, the oxygen and carbon contents are measured by an energy dispersive x-ray detector to determine the O/C ratio. The results show that the NTP reactor produced reactive species such as atomic oxygen and ozone, increasing the surface reactivity and chemical scavenging rate of the EFB. Consequently, the surface morphology changed, with an observed rougher surface from the images of the EFB samples. The change in the appearance of the surface is accompanied by a high O/C ratio, and is caused by reactions of certain components of lignin due to the NTP treatment, The lignin component that was modified is believed to be syringyl, as the syringyl portion in the lignin of EFBs is higher compared to the other components. Syringyl components are detected in the range of F-FIR wavenumbers of 1109-1363 cm-1. With increasing NTP treatment times, the absorbance （of the peaks in the PTIR spectra） for syringyl related C-H and lignin associated C=C bonds decreases as the syringyl decomposes. The resulting release of carboxyl compounds increases the absorbance for the carbonyl C=O group. The results show that NTP treatment is able to modify the surface properties of EFB, and that the surface reactivity can be increased to improve their conversion and processing efficiencies.

Microwave physicochemical activation:an advanced approach to produce activated biochar for palm oil mill effluent treatment

Empty fruit bunch(EFB)is an industrial waste that is abundantly available in Malaysia.Traditionally,EFBs were burned and dumped on the plantation site,resulting in global warming pollution from methane and carbon dioxide.In this study,the EFB was transformed into a high-surface area of activated biochar through a microwave physicochemical approach involving the combination of steam followed by a hydroxide mixture for palm oil mill effluent(POME)treatment.It was found that BET(Brunauer-Emmett-Teller)surface area and total pore volume of activated biochar were 365.60 m^(2)/g and 0.16 cm^(3)/g,respectively.The surface morphology of activated biochar revealed the formation of well-developed pores that can potentially be used as adsorbents to treat POME.The removal efficiency of biochemical oxygen demand(BOD)and chemical oxygen demand(COD)of POME achieved 75%-55%,respectively.This study offers insight into the transformation of industrial waste into value-added products for sustainable environmental remediation.