Degradation Of Palm Oil Mill Effluent Research Articles

Visible light- and dark-driven degradation of palm oil mill effluent (POME) over g-C3N4 and photo-rechargeable WO3.

The investigations of real industrial wastewater, such as palm oil mill effluent (POME), as a recalcitrant pollutant remain a subject of global water pollution concern. Thus, this work introduced the preparation and modification of g-C3N4 and WO3 at optimum calcination temperature, where they were used as potent visible light-driven photocatalysts in the degradation of POME under visible light irradiation. Herein, g-C3N4-derived melamine and WO3 photocatalyst were obtained at different calcination temperatures in order to tune their light absorption ability and optoelectronics properties. Both photocatalysts were proven to have their distinct phases, crystallinity levels, and elements with increasing temperature, as demonstrated by the ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) results. Significantly, g-C3N4 (580°C) and WO3 (450°C) unitary photocatalysts exhibited the highest removal efficiency of POME without dilution due to good crystallinity, extended light absorption, high separation, and less recombination efficiency of electron-hole pairs. Furthermore, surprisingly, the superior energy storage photocatalytic performance with outstanding stability by WO3 achieved an approximately 10% increment during darkness, compared with g-C3N4 under visible light irradiation. Moreover, it has been proven that the WO3 and g-C3N4 photocatalysts are desirable photocatalysts for various pollutant degradations, with excellent visible-light utilization and favorable energy storage application.

Influence of ultrasound modes on sonoelectrochemical degradation of Congo red and palm oil mill effluent

Sonoelectrochemical oxidation (SEO) treatment is a competitive technology for the degradation of organic pollutants in water. The operation modes of ultrasound (continuous and pulse) not only affect the pollutant degradation efficiency but also the energy consumption of SEO. In this study, the influence of ultrasound modes on SEO degradation of Congo red (CR) and real wastewater – palm oil mill effluent (POME) were investigated. The SEO was operated in two modes: continuous ultrasound throughout the whole process and intermittent ultrasound at a cycle of 15 min of ultrasound and 5 min without ultrasound. It was found that the intermittent SEO gave a higher degree of degradation of CR at 95% as compared to continuous SEO and electrochemical oxidation (EO) at 85% and 64%, respectively. The improved performance could be attributed to the supply of ultrasound that minimized electrode passivation and promoted mass transfer and production of hydroxyl radicals. The intermittent supply of ultrasound diminished the interference of ultrasound on the electrochemical process. A similar observation was also observed where the highest COD reduction of POME was recorded by intermittent SEO at about 65%. In terms of energy consumption, degradation of CR by SEO only required half of the energy consumed by the analogous purely electrochemical process at 250–265 kWh/kg dye removed. Surprisingly, the energy consumption for SEO degradation of POME only reduced from 32.82 (electrochemical) to 25.91 and 30.78 kWh/kg COD removed for continuous and intermittent SEO, respectively. Such contrast in energy saving highlights the need for further study as the complex constituents of real effluents will result in different SEO treatment performance. Nonetheless, the capability of SEO in reducing the COD indicates its potential to be used as pre- or post-treatment for other advanced processes in POME handling.

Synthesis of Z-scheme BiOCI/CuFe2O4 Composite with Enhanced Visible Light Photodegradation of Palm Oil Mill Effluent

The palm oil industry generated thick brownish liquid waste known as POME (palm oil mill effluent). POME is one of the wastes that can seriously threaten the survival of aquatic life if discharged untreated. In this study, efficient photocatalytic degradation of POME by CuFe2O4 decorated on BiOCl (BiOCl/CuFe2O4) was reported. The Z-scheme BiOCl/CuFe2O4 composite was successfully fabricated via a precipitation-hydrothermal method. The fourier-transform infrared spectroscopy (FTIR) result clearly displayed the presence of BiOCl and CuFe2O4 in the composite photocatalyst. Compared to pure BiOCl, the composite photocatalyst demonstrated a redshift in the wavelength absorption and great visible light absorbing ability. The photodegradation experiments indicated that the BiOCl/CuFe2O4 demonstrated exceptional POME degradation and decolourization efficiencies of 60% and 68%, respectively after 720 min illumination when compared to the single-phase component photocatalysts. The photocatalytic enhancement of BiOCl/CuFe2O4 can be attributed to the efficient charge carrier separation via the Z-scheme heterojunction.

The role of g-C3N4 in round-the-clock photocatalysis for POME

The main drawback of conventional palm oil mill effluent (POME) treatment is that the process is time and space-consuming. Besides, the treatment produces highly polluted wastewater that pollutes the environment if discharged directly. Photocatalytic process has significant potential to degrade recalcitrant organic pollutants and has recently attracted tremendous attention. However, current approaches mainly focus on visible light condition, which is still an ineffective treatment for POME. In this study, POME was successfully degraded using graphitic carbon nitride (g-C3N4) photocatalyst synthesised by calcination. The prepared photocatalyst was characterised by ultraviolet-visible diffuse reflectance (UV-Vis DRS) spectroscopy and scanning electron microscopy (SEM). The SEM results revealed the morphology of g-C3N4 photocatalyst. g-C3N4 could act as a visible-light-driven (VLD) photocatalyst with the highest photocatalytic efficiency of 71% under visible light. The present work highlights the potential of g-C3N4 towards the degradation of POME under visible light and dark condition. The highly enhanced photocatalytic performance is attributed to g-C3N4, but it does not work well in round-the-clock photocatalysis. However, g-C3N4 can work as the band alignment to drive separate photogenerated charge carriers, leading to effective photocatalytic degradation. g-C3N4 photocatalyst may be considered as an ideal candidate for treating POME.

Palm oil mill effluent treatment using tungsten trioxide: Adsorption and photocatalytic degradation

Abstract Today, some of the major disadvantages of conventional palm oil mill effluent (POME) treatment are that the process is time consuming, as well as space consuming. Besides, most of the recent photocatalyst still have a limitation that able to demonstrate their good performances only under sources of light. The visible-light-driven energy storage photocatalyst, which is tungsten trioxide (WO3), has been developed to overcome the limitations mentioned. Therefore, the present study aims to investigate the comparative calcination temperature and the degradation of POME using WO3 as a photocatalyst in adsorption and photocatalytic processes under visible light irradiation. An eco-friendly WO3 photocatalyst was synthesized by coprecipitation method. Subsequently, the resulting WO3 was characterized by Fourier-transform infrared spectroscopy (FTIR) to evaluate the significance of calcination temperature towards WO3. Furthermore, the adsorption activity of WO3 towards POME was investigated at different sources of ponds (cooling, anaerobic and aeration) throughout 300 min. This study reports on the efficiency of adsorption activity of WO3-400 °C towards pond aeration pollution, which showed that it was better than that in anaerobic and cooling ponds based on the chosen study criteria of color and suspended solid removal for the investigation of photocatalytic activity. Moreover, WO3 was proven to be able to conserve energy, where it was demonstrated that POME can still degrade consistently in darkness, with the highest color removal of approximately 48% was obtained. An extraordinary photocatalytic treatment with WO3 functioning simultaneously as the light harvesting and energy storage material is deemed as an efficient photocatalyst for POME in terms of decolorization and removal of suspended solid.

Bio-remediation of palm oil mill effluent (POME) using Aspergillus niger immobilized on coconut husk and free cell fermentation

Aspergillus niger which is ubiquitous and acts as good biological agent has been chosen to treat POME in this study. Use of, free cell fermentation limits the uptake of substrate as compared to immobilization method which provides larger surface area for cell growth. Therefore, the idea of using coconut husk as immobilization medium has been proposed. Coconut is widely available in Malaysia almost at no cost. Hence, the purpose of this study is to evaluate the bio-degradation of palm oil mill effluent by Aspergillus niger through immobilization on coconut husk and free cell fermentation. Substrates from different types of POME such as. raw, sterile, treated using Aspergillus niger through free cell fermentation and treated with Aspergillus niger cells which are immobilized on coconut husk were prepared at different concentration range from 0 to 100%. Aspergillus niger cells (1 X 105 cells per ml were inoculated into Erlenmeyer flasks and incubated at 30 ± 2 °C and 150 rpm for seven days. Fermentation slurry were used to analyse for turbidity, COD and pH. The results were compared with free cell fermentation method. Raw POME has significantly low turbidity as compared to sterile and treated POME. Autoclaving POME increases the turbidity. 100% sterile POME shows the highest turbidity which is 979.5 FAU and 100% POME which was treated by immobilization on coconut husk shows a reduction in turbidity which gives 900.5 FAU. The presence of coconut husk has significantly increased the COD value as 0% POME (distilled water) with coconut husk shows 3320 mg/l of COD. However, at the end of seven days of treatment, 100% POME which was treated through immobilization shows lower COD as compared to free cell fermentation. pH reading is a concern as treatment method might influence the pH of POME. Range of pH for POME throughout the experiment was between 7.1 and 9.6. Degradation of POME using Aspergillus niger immobilized on coconut husk provides additional incentive that is cheap and sustainable.

Conversion of Palm Oil Mill Effluent on Biogas Production with Consortium Bacteria

Palm Oil Mill Effluent (POME) is a liquid waste that has a high organic content and it can be fermented using bacteria to produce biogas. POME is non-toxic but the high organic contents can disturb the ecosystems and cause the environmental pollution in the water body. POME contains microorganisms that have the potential to hydrolyze oils, celluloses, and protein. Potential bacteria for degradation of POME can be obtained by isolating the waste itself (indigenous bacteria). Indigenous bacteria that have been isolated from POME, namely: Stenotrophomonas rhizopila strain E-P10 (KP 1.2) and Bacillus toyonensis strain BCT-7112 (KAN 1) are used as consortium bacteria in the process of waste degradation. The research sequence consists of rejuvenation of bacteria, preparation of medium mineral, starter and bacterial inoculum. The research aims to degrade the substrates from POME using a consortium and indigenous bacteria to produce biogas. The substrate degradation process is carried out in a bioreactor with degradation time 0, 20, 21-22, 23-26, 27-30, 31-34 and 35-38 days. Bacterial population growth was calculated using a haemacytometer. The highest population of the consortium and indigenous bacteria were found at 7.94x107 mg/mL and 7.23x107 mg/mL. The biogas contents were analyzed using the Gas Chromatography (GC) with units of % mole. The highest production of biogas contains 68.6 % mole methane gas (CH4) and 21.7 % mole carbon dioxide gas (CO2) with the consortium bacteria. While using the KAN 1 bacteria, the highest production of biogas contains 64.0 % mole methane gas (CH4) and 22.0 % mole carbon dioxide gas (CO2).

Synthesis of birnessite-type manganese oxide from two different reducing agents via solvent-free method and the catalytic activity in degradation of POME

Birnessite-type manganese oxide is multifunction material that has been used in various application and the characteristic depends heavily upon its preparation method. In this study, birnessite-type manganese oxide was synthesized using the reaction between KMnO4 (oxidant) and two different reducing agents i.e., citric acid and oxalic acid via a solvent-free method. The characterization of the birnessite was carried out using X-Ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX), and Surface Area Analyzer (SAA). Birnessite from this variation of reducing agents showed different levels of crystallinity, diverse morphology, crystal size, and surface area. The birnessite-type was then applied as a catalyst for the degradation of Palm Oil Mill Effluent (POME) with hydrogen peroxide (H2O2) as an oxidant to reduce the concentrations of Chemical Oxygen Demand (COD). The maximum reduction in COD concentration was obtained using the catalyst concentration of 400 and 800 mg/L for reducing agent of as-synthesized catalyst citric acid and oxalic acid. Birnessite-type manganese oxide shows potential as a catalyst in the degradation of POME with citric acid as reducing agents showed better degradation in reducing COD values.

WO<sub>3</sub>/Nb<sub>2</sub>O<sub>5</sub> Nanoparticles-Decorated Hierarchical Porous ZnO Microspheres for Enhanced Photocatalytic Degradation of Palm Oil Mill Effluent and Simultaneous Production of Biogas

Conventionally, palm oil mill effluent (POME) was treated using open ponding system, which nevertheless long retention times and large treatment areas were required. In this report, heterogeneous photocatalysis was used to degrade the POME and simultaneously assessed the biogas formation. Characterization of the chemically prepared hierarchical porous ZnO microspheres showed that wurtzite was the predominant crystalline phase with a band gap energy of 3.22 eV. Moreover, the as-prepared ZnO were assembled by large numbers of interleaving nanosheets and formed an open porous structure. Under UV irradiation, the as-prepared ZnO demonstrated photocatalytic property on POME degradation. The WO3 and Nb2O5 decorated ZnO photocatalysts (WO3/ZnO and Nb2O5/ZnO) with improved photocatalytic performances were also prepared using a simple and rapid way. Significantly, in the presence of WO3/ZnO and Nb2O5/ZnO composites, the degradation of POME achieved 68.3% and 91.7%, respectively after 240 min irradiation. Interestingly, the assessment of the biogas formation showed that the photocatalytic reactions over Nb2O5/ZnO and WO3/ZnO composites generated higher amount of biogas products (CH4 + CO2) compared to that of ZnO. The photocatalytic enhancement was attributed to the high separation efficiency of photogenerated electron–hole pairs based on the formation of heterojunction structures between the WO3/Nb2O5 and ZnO. The observed findings also revealed that the photocatalytic technology using hierarchical WO3/ZnO and Nb2O5/ZnO composites had the potential to efficiently treat wastewater.

Evaluation of La-Doped CaO Derived from Cockle Shells for Photodegradation of POME

Photocatalysis has merged to be one of the most promising technology in wastewater remediation. However, the application of photocatalysis in treating palm oil mill effluent (POME) is still limited. Many researches were conducted to explore simple and cost-effective alternatives to replace TiO2 for various industrial purposes. Therefore, the aim of this study is to synthesize and characterize lanthanum doped calcium oxide (La/CaO) as photocatalyst as well as to evaluate the performance of these photocatalysts in the degradation of POME. The photocatalyst used in this study was converted from cockle shells to transform into calcium oxide (CaO) through calcination process. The CaO produced was doped with 1 wt%, 3 wt%, and 5 wt% of lanthanum (La) using wet impregnation method to enhance its photocatalytic activity. The photocatalysts were characterised using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Energy-Dispersion X-ray (EDX) and Inductively Coupled Plasma Mass Spectrometry (ICPMS). Then, this photocatalyst was performed on POME under UVC in a batch system by using different La/CaO at optimum catalyst dosage of 3.0 g/L. Through this research, it was found that the POME degradation through photocatalytic reaction was increased with the incorporation of La where 3 wt% La/CaO shows the highest POME degradation compared to others. This is due to the larger BET surface area that provides more active sites resulted from the incorporation of La. The findings of this study imply that the contaminants in POME can be reduced by utilizing CaO derived from cockle shells.

Syngas from catalytic steam reforming of palm oil mill effluent: An optimization study

In this work, the syngas production rate (FSyngas) of LaNiO3-catalysed steam reforming of palm oil mill effluent (POME) was optimized with respect to POME flow rate (V˙POME), catalyst weight (Wcat), and particle size (dcat). With a net acidity, the synthesized LaNiO3 catalysed POME steam reforming by cracking the bulky compounds and valorising simpler intermediates into syngas. The degradation efficiencies (XP) were also evaluated by assessing wastewater parameters, viz. pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), and colour intensity (A). After steam reforming at 873 K, the liquid condensate has neutral pH and zero TSS. The parallel trend of FSyngas and XP verified syngas generation from degradation of POME's organics. At higher V˙POME (0.05–0.09 mL/min), greater POME partial pressure promoted its steam reforming and water gas shift, which enhanced catalytic performance. Beyond optimum V˙POME (0.09 mL/min), coke-forming Boudouard reaction deteriorated catalytic activity. Catalytic performance was boosted for a longer residence time at higher Wcat (0.1–0.3 g); nonetheless, it was reduced by agglomerated catalyst when Wcat > 0.3 g. Finer LaNiO3 (dcat > 74 μm) with greater surface area to volume ratio exhibited better performance; however, ultrafine LaNiO3 (dcat < 74 μm) had poor performance because of occluded pores. Remarkably, optimized POME steam reforming over LaNiO3 (T = 873 K, V˙POME = 0.09 mL/min, Wcat = 0.3 g, dcat = 74–105 μm) has generated 132.47 μmoL/min of H2-rich syngas, whilst achieved 99.53% XCOD, 99.88% XA, 99.75% XBOD5, and 100% XTSS.

Photocatalytic treatment of palm oil mill effluent by visible light-active calcium ferrite: Effects of catalyst preparation technique

Palm oil mill effluent (POME) is a serious and expensive environmental problem in Malaysia. In this paper, CaFe2O4 is introduced as a novel photocatalyst for the degradation of POME under visible light irradiation. Two synthesis routes, auto-combustion and co-precipitation, and two calcination temperatures 550 °C and 700 °C were used to produce four CaFe2O4 catalysts AC550, AC700, CP550 and CP700. CP550 exhibited the greatest photocatalytic degradation at 56% chemical-oxygen-demand (COD) removal after 8 h of irradiation which dropped to 49% after three consecutive cycles indicating reasonable conversion and high recyclability. BET analysis indicated CP550 had the highest SBET (27.28 m2/g) and pore volume (0.077 cm3/g) which dropped precipitously for CP700 upon increasing the calcination temperature to an SBET of 9.73 m2/g and pore volume of 0.025 cm3/g due to annealing which created a smoother surface area as evidenced by the SEM images. UV–Vis DRS indicated CP550 had the highest band-gap (1.52 eV) which is likely due to the presence of a highly crystalline pure CaFe2O4 phase compared to the other products which existed as a mixture of Fe oxidation states evidenced by the XRD data. The PL spectra for all catalysts indicated significantly lower recombination rate for both CP550 and CP700. Introduction of IPA into the reaction mixture to eliminate hydroxyl radicals resulted in a diminishing of COD removal from 56% to 7% proving hydroxyl radicals to be the primary reactive species responsible for photodegradation of POME.

Parameter Affecting Photocatalytic Degradation of POME using LaCa as Photocatalyst

Abstract Palm oil industry is linked to several environmental issues especially in water pollution although its production is crucial for the economy of Malaysia. The disposal of the highly contaminating palm oil mill effluent (POME) from this sector needs to be remedied properly to minimize its environmental impacts. Therefore, this study was conducted to synthesize and characterize the photocatalyst derived from cockle shells waste and using lanthanum (La) as dopant. Besides that, the performance of 3wt% of La doped calcium oxide (3LaCa) as photocatalyst in the degradation of POME was evaluated with different stirring speed from COD removal efficiencies under UVC irradiation of 240 minutes in batch system. The results revealed that 3LaCa has the potential to be used as an alternative photocatalyst besides titanium oxide (TiO2). It was shown that 300 rpm as optimum stirring speed with removal photocatalytic activity at 54.0%. Kinetic studies have shown that the photocatalytic degradation of POME follows first-reaction order kinetics with correlation coefficient of 0.97 and specific reaction rates 3.6 x 10-3 min-3.

Life cycle inventory of the commercial production of compost from oil palm biomass: a case study

This paper compared the life cycle inventory (LCI) obtained from three commercial oil palm biomass composting projects in Malaysia which use the open windrow composting system. The LCI was obtained and calculated based on the functional unit of 1 t of compost produced. The input of the inventory are the feed materials such as empty fruit bunches (EFB) and palm oil mill effluent (POME); and utilities which include electricity generated at palm oil mill and diesel used. Composting 2.0–2.5 t of EFB and 5.0–7.5 t of POME required diesel from 218.7 to 270.2 MJ and electricity from 0 to 6.8 MJ. It is estimated that the composting emitted from 0.01 to 0.02 t CO2eq/tcompost mainly from diesel used to operate machineries. Composting saved 65 % of time required for a complete degradation of POME when compared to ponding system, and 89 % of time required for a complete degradation of EFB compared to mulching. In terms of land required, it required 36 % less land as compared to ponding for POME and 99 % less land as compared to mulching for EFB. Based on the case study, diesel was found to be the main contributor to the environmental impact. There is a potential of upgrading the process to be more economical and environmental friendly. Using electricity as the source of energy has a lower footprint for the composting process. Instead of using raw POME, studies had reported that using treated POME either from anaerobic ponding or digested tank can accelerate the composting process.

Start-up Operation of Anaerobic Degradation Process for Palm Oil Mill Effluent in Anaerobic Bench Scale Reactor (ABSR)

The start-up operation or acclimatization process of anaerobic stabilization pond treatment for palm oil mill effluent (POME) was carried out in a laboratory anaerobic bench scale reactor (ABSR). The start-up operation of the ABSR was operated at two different organic loading rates (ORG) of 0.89 – 0.92 kg COD/m3/day and 1.34 – 1.37 kg COD/m3/day which corresponds to hydraulic retention time (HRT) of 60 and 40 days. The investigation showed that the acclimatize process for anaerobic degradation of POME was completed after 48 days of operation. In present study, the indicators that been used were pH, microbial growth, effluent of total chemical oxygen demand (COD), COD removal efficiency, alkalinity and ratio fraction between volatile fatty acid and alkalinity.