Transportation fuel production by combination of LDPE thermal cracking and catalytic hydroreforming

Fuel production from plastics is a promising way to reduce landfilling rates while obtaining valuable products. The usage of Ni-supported hierarchical Beta zeolite (h-Beta) for the hydroreforming of the oils coming from LDPE thermal cracking has proved to produce high selectivities to gasoline and diesel fuels (>80%). In the present work, the effect of the Ni loading on Ni/h-Beta is investigated in the hydroreforming of the oils form LDPE thermal cracking. h-Beta samples were impregnated with Ni nitrate, calcined and reduced in H₂ up to 550 °C to achieve different Ni contents: 1.5%, 4%, 7% and 10%. Larger and more easily reducible metal particles were obtained on Ni 7%/h-Beta and Ni 10%/h-Beta. Hydroreforming tests were carried out in autoclave reactor at 310 °C, under 20 bar H₂, for 45 min. Ni content progressively increased the amount of gases at the expenses of diesel fractions, while gasoline remained approximately constant about 52–54%. Maximum selectivity to automotive fuels (～81%) was obtained with Ni 7%/h-Beta. Ni loading also enhanced olefins saturation up to Ni 7%/h-Beta. High cetane indices (71–86) and octane numbers (89–91) were obtained over all the catalysts. Regarding the different studied Ni contents, Ni 7%/h-Beta constitutes a rather promising catalyst for obtaining high quality fuels from LDPE thermal cracking oils.     

Hydroreforming over Ni/H-beta of the thermal cracking products of LDPE, HDPE and PP for fuel production

The thermal cracking at 400?°C of pure polyolefins—low density polyethylene (LDPE), high density polyethylene (HDPE) and polypropylene (PP) and a standard polyolefin mixture (46?% LDPE?+?27?% HDPE?+?28?% PP)—was studied together with the catalytic hydroreforming of the obtained oils over Ni/h-beta at 310?°C under 20?bar of hydrogen. The oils obtained after the thermal cracking of PP contain the highest amount of gasoline (58?%), while those coming from HDPE the lowest (39?%). The bromine index of the oils was very high, ranging from 54.1 (LDPE) to 83.8 (PP), indicating a high olefinic content of the oils. Additionally, the thermal cracking of the mixture indicates the occurrence of a synergestic effect among plastics, with transfer of methyl groups from PP to polyethylenes. Ni/h-beta (Si/Al?=?25; Ni content?=?6.2?wt%) catalyst was used in the hydroreforming since it contains a bimodal pore size distribution (0.6/3.1?nm), which improves accessibility of the oil molecules to the catalytic sites. After the hydroreforming and regardless of the plastics used, the share of lighter products (gasoline and gases) increases, reaching a remarkable 68?% of gasolines with the oils coming from PP. Regardless of the starting feed, the amount of useful fuels (gasoline?+?light diesel) was within 80–85?%. Additionally, the oils were successfully hydrogenated since the bromine indexes dropped below 7, indicating that more than 90?% of the starting olefins were saturated. The usage of catalysts increased the amount of aromatics in the obtained oils within 13–20?%, depending on the starting plastic. Likewise, the isoparaffin content of the gasolines was within 35–40?%, except for PP, where it was enhanced to 62?%. However, the research octane number (RON) of the gasolines from LDPE and PP and the cetane indexes of the diesel from all the plastics were promising for their application as fuels.     

An engineered plant that accumulates higher levels of heavy metals than Thlaspi caerulescens, with yields of 100 times more biomass in mine soils

Nicotiana glauca transformed with TaPCS1 was tested for its application in phytoremediation. When plantlets were grown in mine soils containing Cu, Zn, and Pb (42, 2600, and 1500 mg kg(-1)) the plant showed high levels of accumulation especially of Zn and Pb. Adult plants growing in mine soils containing different heavy metal concentrations showed a greater accumulation as well as an extension to a wider range of elements, including Cd, Ni and B. The overexpressed gene confers up to 9 and 36 times more Cd and Pb accumulation in the shoots under hydroponic conditions, and a 3- and 6-fold increase in mining soils. When the hyperaccumulator Thlaspi caerulescens was compared, the results were higher values of heavy metal and Boron accumulation, with a yield of 100 times more biomass. Thlaspi was unable to survive in mining soils containing either a level higher than 11000 mg kg(-1) of Pb and 4500 mg kg(-1) of Zn, while engineered plants yielded an average of 0.5 kg per plant.     

Structural and seasonal variations of inshore fish populations in Málaga Bay,Southeastern Spain

A seasonal study of the inshore fish community was conducted in 1981 and 1982 at two stations in Málaga Bay (SE Spain). A total of 66 fish species were caught. Two families, Clupeidae (68.6%) and Engraulidae (28.5%), dominated in numbers, and Carangidae (54.3%) and Sparidae (29.1%) in biomass for both zones. There were two periods of high fish density in each zone: winter (2.2 g m^-2) and autumn (2.0 g m^-2) in the western zone and spring (2.95 g m^-2) and summer (3.6 g m^-2) in the eastern zone. Species diversity was relatively high during spring (2.95 and 3.00) and summer (2.32 and 2.44), showing clear variation with other zones of the Spanish coasts. An increase in diversity and number of fish species from north to south was observed. The area studied (0 to 15 m deep) serves as a nursery for larvae and young fish of several species appearing in the catches. The zoogeographical affinities of the fish species caught are: tropicals 25.7%, boreals 24.2%, Iberian-Moroccan 14%, endemics 4.5%.     

Street floods in Metro Manila and possible solutions

Urban floods from thunderstorms cause severe problems in Metro Manila due to road traffic. Using Light Detection and Ranging (LiDAR)-derived topography, flood simulations and anecdotal reports, the root of surface flood problems in Metro Manila is identified. Majority of flood-prone areas are along the intersection of creeks and streets located in topographic lows. When creeks overflow or when rapidly accumulated street flood does not drain fast enough to the nearest stream channel, the intersecting road also gets flooded. Possible solutions include the elevation of roads or construction of well-designed drainage structures leading to the creeks. Proposed solutions to the flood problem of Metro Manila may avoid paralyzing traffic problems due to short-lived rain events, which according to Japan International Cooperation Agency (JICA) cost the Philippine economy 2.4 billion pesos/day.     

An indicator-based sustainability assessment method for indigenous communities: a case study from Mexico

Environment, Development and Sustainability - Indigenous and Western communities are faced with increasing issues of sustainability compromising their natural resources and cultural heritage, for...