Catalytic upgrading of bio-oil from halophyte seeds into transportation fuels

Because of socioeconomic considerations,wide-scale production of biofuel necessitates the utilization of nonedible biomass feedstock that does not compete for land and fresh water resources.In this regard,Salicornia bigelovii(SB)is the most investigated halophyte species.The high oil content in SB seeds has sparked mounting research that aims to utilize SB as an industrial crop in the production of bio-oil,particularly in coastal areas where these plants thrive.However,the oil extracted from the pyrolysis of raw SB seeds is largely dominated by oxygenated fatty acids,most notably 9,12-octadecadienoic acid and 9,17-octadecadienal,typical to that of other crops.The pyrolysate bio-oil of the raw SB seeds exhibited a relative yield of oxygenated compounds that decreased from 57.05%at 200℃to 9.81%at 500℃,and the relative yield of nitrogenated compounds increased from 4.86%at 200℃to 21.97%at 500℃.To improve the quality of the produced bio-oil,herein we investigated the catalytic hydrodeoxygenation(HDO)of the fragments that were produced from the thermal degradation of SB seeds.A 5%Ni–CeO_(2)catalyst was prepared and characterized by a wide array of methods X-ray diffraction,X-ray photoelectron spectroscopy,temperature programmed reduction,scanning electron microscope,BrunauerEmmett-Teller analysis,and thermogravimetric analyzer.The catalytic run was executed between 200 and 500℃in a flow reactor.The deployed catalytic methodology displayed a profound HDO capacity.At 400℃,for instance,the gas chromatography mass spectroscopy(GC–MS)detected loads of paraffin and aromatic compounds exists at appreciable values of 48.0%and 28.5%,respectively.With a total relative yield of 43.2%(at 400℃),C8–C15 species(i.e.,jet fuel fractions)were the most abundant species in the upgraded SB bio-oil.The release of H_(2),CO,CO_(2),and CH_(4)was analyzed qualitatively and quantitatively using gas chromatography thermal conductivity detector and Fourier infrared spectroscopic analysis.When the Ni–CeO_(2)catalyst was utilized,a complete deoxygenated bio-oil was obtained from SB seeds using the surface-assisted HDO reaction.On the basis of the elemental analysis,the biochar’s hydrogen and oxygen contents were found to decrease significantly.Density functional theory computations showed mechanisms for reactions that underpinned the experimentally observed hydrodeoxygenation process.Outcomes presented herein shall be instrumental toward the effective utilization of halophyte in the production of commercial transportation fuels.

Prospects and limitations of soil amendment and irrigation techniques for the water-saving public urban greenery and ephemeral weed management in the sandy soils of the United Arab Emirates

Public urban greenery greatly contributes to the residential and tourist value of cities in the Gulf Region,but due to the hyper-arid climatic conditions,the cost of irrigation and plant maintenance is very high.Existing strategies to reduce the monetary and ecological costs involve the cultivation of native xerophytic plantations,and/or the use of soil improvers to increase water-and nutrient-holding capacity of the sandy soils.Various soil improvers based on mineral,organic,or synthetic materials have entered the United Arab Emirates(UAE)market in recent years,but there is considerable uncertainty about how they should best be used in combination with ornamental plant stands involving xerophytic native plants.The present study investigated the effect of soil amendment and deep pipe irrigation on perennial ornamental plant stands involving native plants(Tephrosia appolinea(Gel.)Link in combination with Aerva javanica(Burm.f.)Juss.ex Schult.)and native-exotic plants(T.appolinea in combination with Ruelia simplex C.Wright)either or not topsoil and subsoil amendment with bentonite and hydrophobic sand under the irrigation water supply of less than 50%of reference evapotranspiration(ET0).After one year of cultivation,T.appolinea and A.javanica(native vs.native)produced high biomass and exhibited high water use efficiency(WUE)as compared with T.appolinea and R.simplex(native vs.exotic)combination given that no significant differences were found under the soil amendment treatments.All stands thrived under irrigation water supply far below what is usually supplied to exotic ornamental stands in public parks of the Al Ain City,the UAE.However,subsoil amendment in combination with deep pipe irrigation reduced the occurrence of weeds and increased the overall plant rooting depth.Our results suggest that subsoil amendment and irrigation up to 60-80 cm depth can potentially control ephemeral weed infestation,which is a great challenge in various plant production systems of the Gulf Region.The results of the present study suggest that the impact of soil amendment on the WUE of exotic plants is marginal and might not be economically justified.Replacing exotic with native ornamental plant species seems to have a far greater water-saving potential than the amendment of the soil,while weeds can be suppressed in the absence of topsoil moisture.