Photocatalytic degradation of organic pollutants using green oil palm frond-derived carbon quantum dots/titanium dioxide as multifunctional photocatalysts under visible light radiation

The present work suggested the use of waste oil palm frond as an alternative precursor for nitrogendoped carbon quantum dots(NCQDs)and proposed a straightforward in-situ hydrothermal method for the preparation of NCQDs/TiO_(2)nanocomposites.The elemental composition,morphological,structural and optical characteristics of NCQDs/TiO_(2)nanocomposites have been comprehensively investigated.The successful grafting of NCQDs on TiO_(2)matrix was confirmed by the formation of Ti AOAC bond and the electronic coupling between theπ-states of NCQDs and the conduction band of TiO_(2).For the first time,the oil palm frond-derived NCQDs/TiO_(2)was adopted in the photodegradation of methylene blue(MB)under visible-light irradiation.As a result,the photocatalytic efficiency of NCQDs/TiO_(2)nanocomposites(86.16%)was 2.85 times higher than its counterpart TiO_(2)(30.18%).The enhanced performance of nanocomposites was attributed to the pivotal roles of NCQDs serving as electron mediator and visiblelight harvester.Besides,the optimal NCQDs loading was determined at 4 ml while the removal efficiency of NCQDs/TiO_(2)-4 was the highest at a catalyst dosage of 1 g.L^(-1)under alkaline condition.This research work is important as it proposed a new insight to the preparation of biomass-based NCQDs/TiO_(2)using a facile synthetic method,which offers a green and sustainable water remediation technology.

Comparable Study of Xylanase Production from Aspergillus niger via Solid State Culture

With the high availability of agricultural wastes in Malaysia, green energy is practical to be conducted. Thus, a research on the modification of the physical conditions of the solid state culture system, specifically different initial moisture content, fermentation temperature, inoculums size and different percentage of carbon and nitrogen sources were conducted to compare the usage of two different lignocellulosic materials which were oil palm frond and banana petiole respectively. After using a conventional method （one factor at a time）, the optimum fermentation conditions would be a combination of 70% initial moisture content （v/w）, at 28 ~C fermentation temperature with supplementation of 1% sucrose （w/w） and 1% peptone using 1 mL of inoculum in order to achieve highest xylanase production which was 1,711.87 U/mL and 1,579.60 U/mL for oil palm frond and banana petiole respectively. It was suggested that oil palm frond showed higher xylanase production compared to banana petiole.

Barbara Longhi’s Saint Justina of Padua:Pagan Symbolism and Christian Martyrology

Barbara Longhi of Ravenna(1552-1638)skillfully created small devotional altarpieces depicting holy saints with their respective attributes of martyrdom,seen in Saint Agnes of Rome(c.291-304)with an ewe,Saint Cecilia(c.200-235)with a portable organ,Saint Catherine of Alexandria(c.287-304)with a broken spiked wheel,and Saint Justina of Padua(c.3rd century)with a small sword in her chest.For their physical sacrifice,Heaven rewarded them with a palm frond as an honorific spiritual gift.Barbara included some of these saints in her paintings on the theme of holy conversation(sacra conversazione;a religious gathering with the Madonna and Child)and depicted the female saints as a single panel-solo image-for private devotion or supplicatory assistance.Most of the biographies and historicity about the lives of these saints are recounted by Jacobus de Voragine(1222-1298),Archbishop of Genoa,in his Golden Legend(Legenda Aurea,1275).This essay only comments on the iconography of one of Barbara’s female saints,Saint Justina of Padua.

Phenol contaminated municipal wastewater treatment using date palm frond biochar:Optimization using response surface methodology

Phenol is classified as an emerging contaminant which can be very toxic even at low concentrations and should be removed from wastewaters before reaching the environment.In this study date palm frond and leaf were pyrolyzed at different temperatures to identify the best adsorbent(feedstock)and pyrolysis temperature to remove phenol from aqueous solutions.Date palm frond pyrolyzed at 600℃,termed DPF600,achieved the highest phenol removal rates of 64%and adsorption capacity of 15.93 mg/g.Response surface methodology approach using Box-Behnken design was implemented to obtain the optimal pH(6),contact time(20 h)and dosage(0.1 g)for the maximum phenol adsorption.A predicted adsorption capacity was found as 16.62 mg/g which was in close agreement with the experimental adsorption capacity of 17.38 mg/g.Isotherm and kinetic models in both linear and non-linear forms indicated that Freundlich model(R^(2)=0.99,χ^(2)=0.02,RMSE=1.09)and pseudo-second order model(R^(2)=0.99,χ^(2)=0.85,RMSE=5.41)fit best the obtained experimental data.Thermodynamics calculations affirmed that the adsorption of phenol onto DPF600 biochar was endothermic and spontaneous.The point of zero charge was found to be at 6.5 for DPF600 biochar.Scanning electron microscopy coupled with energy dispersive X-ray,Fourier transform infrared spectroscopy and X-ray diffraction confirmed adsorption of phenol onto DPF600 biochar.Application of DPF600 biochar to remove phenol from synthetic primary and secondary treated wastewater samples achieved 60 and 85%removal rates and 241 mg/g and 22.28 mg/g adsorption capacities,respectively.Regeneration studies showed promising adsorption capacities indicating the efficacy of DPF600 for the removal of phenol from wastewater.