Restoration of Liquid Effluent from Oil Palm Agroindustry in Malaysia using UV/TiO2 and UV/ZnO Photocatalytic Systems: A Comparative Study

In this study, we have employed a photocatalytic method to restore the liquid effluent from a palm oil mill in Malaysia. Specifically, the performance of both TiO2 and ZnO was compared for the photocatalytic polishing of palm oil mill effluent (POME). The ZnO photocatalyst has irregular shape, bigger in particle size but smaller BET specific surface area (9.71 m2/g) compared to the spherical TiO2 photocatalysts (11.34 m2/g). Both scavenging study and post-reaction FTIR analysis suggest that the degradation of organic pollutant in the TiO2 system has occurred in the bulk solution. In contrast, it is necessary for organic pollutant to adsorb onto the surface of ZnO photocatalyst, before the degradation took place. In addition, the reactivity of both photocatalysts differed in terms of mechanisms, photocatalyst loading and also the density of photocatalysts. From the stability test, TiO2 was found to offer higher stability, as no significant deterioration in activity was observed after three consecutive cycles. On the other hand, ZnO lost around 30% of its activity after the 1st-cycle of photoreaction. The pH studies showed that acidic environment did not improve the photocatalytic degradation of the POME, whilst in the basic environment, the reaction media became cloudy. In addition, longevity study also showed that the TiO2 was a better photocatalyst compared to the ZnO (74.12%), with more than 80.0% organic removal after 22 h of UV irradiation

Experimental evaluation and empirical modelling of palm oil mill effluent steam reforming

The current work describes a novel application of steam reforming process to treat palm oilmill effluent (POME), whilst co-generating H2-rich syngas from the treatment itself. The effects of reaction temperature, partial pressure of POME and gas-hourly-space-velocity (GHSV) were determined. High crystallinity 20 wt%Ni/80 wt%Al2O3 catalyst with smooth surface was prepared via impregnation method. Baseline runs revealed that the prepared catalyst was highly effective in destructing organic compounds, with a two-fold enhancement observed in the presence of 20 wt% Ni/80 wt%Al2O3 catalyst, despite its low specific surface area (2.09 m2 g−1). In addition, both the temperature and partial pressure of POME abet the COD reduction. Consequently, the highest COD reduction of 99.7% was achieved, with a final COD level of 73 ± 5 ppm from 27,500 ppm, at GHSV of 40,000 mL/h.gcat and partial pressure of POME equivalent to 95 kPa at 1173 K. In terms of gaseous products, H2 was found to be the major component, with selectivity ranged 51.0%–70.9%, followed by CO2(17.7%–34.1%), CO (7.7%–18.4%) and some CH4 (0.6%–3.3%). Furthermore, quadratic models with high R2-values were developed

Preparation of Titania Doped Argentum Photocatalyst and its Photoactivity Towards Palm Oil Mill Effluent Degradation

This paper reports on the photocatalytic degradation of pre-treated palm oil mill effluent (POME) over titania loaded with photocatalyst. The argentum loading on the titania was varied from 0.25 to 1.0 wt% via wet-impregnation technique. X-ray diffraction characterization of all the photocatalysts showed that the photo-active rutile phase was still intact after the photocatalyst synthesis. In addition, the UV–Vis diffuse reflectance measurements indicate an improved visible light energy absorption and that the band gap energy was significantly reduced (averaging 2.50 eV) when titania was loaded with argentum, compared to the pristine titania that recorded a reading of 3.20 eV. The 0.50 wt% argentum/titania photocatalyst offered the most effective degradation of pre-treated POME under the irradiation of 100 W of UV light (25.0%) and also visible light (16.0%), respectively, over a loading of 0.2 g/L. Significantly, the maximum photocatalyst loading determined from the current work was 1.0 g/L

Diaqua­(1,4,8,11-tetra­aza­cyclo­tetra­deca­ne)nickel(II) fumarate tetra­hydrate

The asymmetric unit of the title complex salt, [Ni(C10H24N4)(H2O)2](C4H2O4)·4H2O, comprises half of a nickel(II) complex dication, half of a fumarate dianion and two water mol­ecules. Both the NiII cation and fumarate anion lie on a crystallographic inversion center. The NiII ion in the cyclam complex is six-coordinated within a distorted N4O2 octa­hedral geometry, with the four cyclam N atoms in the equatorial plane and the two water mol­ecules in apical positions. The six-membered metalla ring adopts a chair conformation, whereas the five-membered ring exists in a twisted form. In the crystal packing, inter­molecular O—H⋯O hydrogen bonds between the water molecules and the carboxyl groups of the fumarate anions lead to the formation of layers with R 4 2(8) ring motifs. NiII complex cations are sandwiched between two such layers, being held in place by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, consolidating a three-dimensional network

Nitrogen-phosphorous co-doped palladium electrocatalyst for glycerol electro-oxidation reaction (GEOR): An efficient system for mesoxalic acid and dihydroxyacetone production

Electro-oxidation reaction of glycerol (GEOR) is a promising and eco-friendly technique for producing commercially valuable organic acids. In contrast to conventional non-metallic doping into single or multiwalled carbon nanotubes, our work reported the incorporation of N, and P into the Pd/CNTs framework for selective oxidation of glycerol to 1, 3-dihydroxyacetone and mesoxalic acid. Electrochemical and physicochemical characterization showed that the NP doped/PdCNTs has superior electrocatalytic performance for GEOR in alkaline media compared to counter catalysts. NP doped/PdCNTs exhibits better resistivity (If/Ib = 1.71) and requires only 0.09 V electrocatalysis voltage to achieve 76.67 mA cm−2 current density, demonstrating an energy-efficient and cost-competitive method to produce mesoxalic acid and dihydroxyacetone. At 0.09 V vs Ag/AgCl in 0.5 M Gly/0.5 M KOH, the Pd mass activity of NP doped/PdCNTs was 307.30 mAmg-1 Pd, representing 2.45, 1.06, and 1.051 times higher than Pd/CNTs, N doped/PdCNTs, and P doped/PdCNTs, respectively. The yield of 1, 3-dihydroxyacetone was 29.76 times higher than Pd/CNTs, 24.06 times higher than N doped/PdCNTs, and 1.06 times higher than P doped/PdCNTs

Long-term evaluation of palm oil mill effluent (POME) steam reforming over lanthanum-based perovskite oxides

To replace the obsolete ponding system, palm oil mill effluent (POME) steam reforming (SR) over net-acidic LaNiO3 and net-basic LaCoO3 were proposed as the POME primary treatments, with promising H2-rich syngas production. Herein, the long-term evaluation of POME SR was scrutinized with both catalysts under the optimal conditions (600 °C, 0.09 mL POME/min, 0.3 g catalyst, & 74–105 μm catalyst particle size) to examine the catalyst microstructure changes, transient process stability, and final effluent evaluation. Extensive characterization proved the (i) adsorption of POME vapour on catalysts before SR, (ii) deposition of carbon and minerals on spent SR catalysts, and (iii) dominance of coking deactivation over sintering deactivation at 600 °C. Despite its longer run, spent LaCoO3 (50.54 wt%) had similar carbon deposition with spent LaNiO3 (50.44 wt%), concurring with its excellent coke resistance. Spent LaCoO3 (6.12 wt%; large protruding crystals) suffered a harsher mineral deposition than spent LaNiO3 (3.71 wt%; thin film coating), confirming that lower reactivity increased residence time of reactants. Transient syngas evolution of both SR catalysts was relatively steady up to 4 h but perturbed by coking deactivation thereafter. La2O2CO3 acted as an intermediate species that hastened the coke removal via reverse Boudouard reaction upon its decarbonation. La2O2CO3 decarbonation occurred continuously in LaCoO3 system but intermittently in LaNiO3 system. LaNiO3 system only lasted for 13 h as its compact ash blocked the gas flow. LaCoO3 system lasted longer (17 h) with its porous ash, but it eventually failed because KCl crystallites blocked its active sites. Relatively, LaCoO3 system offered greater net H2 production (72.78%) and POME treatment volume (30.77%) than LaNiO3 system. SR could attain appreciable POME degradation (>97% COD, BOD5, TSS, & colour intensity). Withal, SR-treated POME should be polished to further reduce its incompliant COD and BOD5

The distinctive gastric fluid proteome in gastric cancer reveals a multi-biomarker diagnostic profile

<p>Abstract</p> <p>Background</p> <p>Overall gastric cancer survival remains poor mainly because there are no reliable methods for identifying highly curable early stage disease. Multi-protein profiling of gastric fluids, obtained from the anatomic site of pathology, could reveal diagnostic proteomic fingerprints.</p> <p>Methods</p> <p>Protein profiles were generated from gastric fluid samples of 19 gastric cancer and 36 benign gastritides patients undergoing elective, clinically-indicated gastroscopy using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry on multiple ProteinChip arrays. Proteomic features were compared by significance analysis of microarray algorithm and two-way hierarchical clustering. A second blinded sample set (24 gastric cancers and 29 clinically benign gastritides) was used for validation.</p> <p>Results</p> <p>By significance analysyis of microarray, 60 proteomic features were up-regulated and 46 were down-regulated in gastric cancer samples (<it>p </it>< 0.01). Multimarker clustering showed two distinctive proteomic profiles independent of age and ethnicity. Eighteen of 19 cancer samples clustered together (sensitivity 95%) while 27/36 of non-cancer samples clustered in a second group. Nine non-cancer samples that clustered with cancer samples included 5 pre-malignant lesions (1 adenomatous polyp and 4 intestinal metaplasia). Validation using a second sample set showed the sensitivity and specificity to be 88% and 93%, respectively. Positive predictive value of the combined data was 0.80. Selected peptide sequencing identified pepsinogen C and pepsin A activation peptide as significantly down-regulated and alpha-defensin as significantly up-regulated.</p> <p>Conclusion</p> <p>This simple and reproducible multimarker proteomic assay could supplement clinical gastroscopic evaluation of symptomatic patients to enhance diagnostic accuracy for gastric cancer and pre-malignant lesions.</p

An application of advanced oxidation process to photopolish palm oil mill effluent over TIO2 and ZnO photocatalysts

The reactivity of both UV/TiO2 and UV/ZnO systems in treating palm oil mill effluent (POME) were investigated in current study. XRD revealed that TiO2 and ZnO, with the band gap energy of 3.15 and 3.20 eV respectively, were free from impurities. ZnO photocatalyst has irregular shape, bigger in particle size but lower BET specific surface area (9.71 m2/g) compared to the spherical TiO2 photocatalysts (11.34 m2/g). The degradation process of POME was conducted in a 500 mL Pyrex photoreactor at room temperature with the irradiation of 100 W UV lamp. With 1.0 g/L of photocatalyst and 70 mL/min of O2 bubbling, the degradation obtained by UV/TiO2 system (52.0%) is slightly higher compared to UV/ZnO system (50.0%) in 240 min of UV irradiation and the performance gap between two systems was broaden after 22 h of UV irradiation. At the end of the experiments, the degradation achieved were 80.35% and 74.11% for UV/TiO2 and UV/ZnO system, respectively. Nonetheless, the final COD, BOD and oil and grease (O&G) level of POME for UV/TiO2 system (33, 16, and 10 ppm) and UV/ZnO system (44, 26, and 20 ppm) were successfully brought down to the safe level for discharging. In recyclability test, TiO2 exhibits a higher stability, as no significant deactivation was observed after three consecutive cycle of photoreaction, compared to 24.0% of deactivation in UV/ZnO system. Scavenging test reveals that the main reactive species for POME degradation for both systems are different. OH• free radical decomposed most organics in UV/TiO2 while UV/ZnO system generates OHads• for most of the organic degradation. The ability of organic-adsorption in ZnO photocatalyst allows the degradation process occurs on its surface. For TiO2 photocatalyst, the organic degradation can only happen in bulk solution due to the poor affinity of TiO2 towards organic pollutants. This is further supported by the post-reaction analysis conducted on spent photocatalysts both systems, confirming the carbonaceous species only detected on the surface of ZnO. 23 full factorial design in Response Surface Methodology (RSM) was employed and confirmed that O2 flowrate, photocatalyst loadings and initial concentration of POME are significant in both system. Furthermore, it also confirmed the existence of interactive factors in both systems. Subsequently, all three main factors for both systems were optimized by using Central Composite Design (CCD) in RSM. Quadratic models with high R2 values (>0.9) and excellent residue analysis were developed for both systems to describe the degradation. The optimized conditions were suggested and experiments (duplicated) were conducted for both system. Based on the results obtained, the degradation of UV/TiO2 system were successfully optimized to averaged degradation of 55.0% after 240 min of UV irradiation in the presence of 1.04 g/L of TiO2, 66.0 mL/min of O2 bubbling and initial POME concentration of 240 ppm. On the other hand, the degradations of UV/ZnO system were optimized to averaged degradation of 55.29%, with 60 mL/min of O2 bubbling, 1.26 g/L of ZnO and 220 ppm of POME, after 240 min of UV irradiation. The errors between the estimated and experimental degradation recorded for UV/TiO2 system and UV/ZnO system were very low (4.41 and 5.40%, respectively), hence confirming the adequacy of the models developed

Photo-treatment of palm oil mills effluent (pome) over cu/tio2 photocatalyst

The current work reports the use of titania based photocatalysts for the photo-treatment of palm oil mill effluent collected from Felda Lepar Hilir 3, a local source. Different metal loadings of copper viz. 2wt%, 5wt%, 10wt%, 15wt%, 20wt% and 25wt% were doped onto titania employing wet impregnation method. The synthesized catalysts were subjected to physicochemical characterization. Gas pycnometer density measurements revealed that the actual density of catalysts were lower than theoretical density due to the porous structure as proven by the subsequent liquid N2 physisorption. In addition, X-ray diffraction pattern showed formation of CuO with crystallite size ranging from 41.8 to 49.1 nm upon calcination. Significantly, liquid N2 physisorption showed that the BET specific surface area of catalysts prepared decreased with wt% of Cu probably due to pore blockage Moreover, 5wt% Cu/TiO2 exhibits the largest pore volume, which is 0.049 cm3/g for both adsorption and desorption volume. In the term of pore size, 20wt% of Cu/TiO2 has the largest adsorption pore size, which is 23.39 nm while 5wt% of Cu/TiO2 has the largest desorption pore size, which is 19.83 nm. Based on the UV-irradiated photoreaction results, 20wt% Cu/TiO2 yielded the highest organic degradability (conversion) among all the synthesized catalysts. Overall, 27.0% conversion was achieved within 1 h of photoreaction. Based on the integral method, it seems that the POME photo-reaction followed the 2nd-order reaction. Moreover, 20 wt% Cu/TiO2 exhibited the highest specific reaction constant at 2.60×10-5 (ppm.min)-1. Besides, an optimum catalyst loading were also discovered in current project. For 20wt% Cu/TiO2, the optimum catalyst loading is 0.83g/L of POME solution. Finally, a longevity test was conducted and it was found that more than 40% of the organic contaminant was decomposed after 7 h of UV-irradiation. Moreover, CO and CO2 were detected in the gas products from GC analysis. As conclusion, phototreatment for POME shows positive results in current project and is suitable to replace the existing traditional POME method for better efficienc