The use of a natural coagulant (Opuntia ficus-indica) in the removal for organic materials of textile effluents

The goal of this study was to investigate the activity of the coagulant extracted from the cactus Opuntia ficus-indica (OFI) in the process of coagulation/flocculation of textile effluents. Preliminary tests of a kaolinite suspension achieved maximum turbidity removal of 95 % using an NaCl extraction solution. Optimization assays were conducted with actual effluents using the response surface methodology (RSM) based on the Box–Behnken experimental design. The responses of the variables FeCl₃, dosage, cactus dosage, and pH in the removal of COD and turbidity from both effluents were investigated. The optimum conditions determined for jeans washing laundry effluent were the following: FeCl₃ 160 mg L^?1, cactus dosage 2.60 mg L^?1, and pH 5.0. For the fabric dyeing effluent, the optimum conditions were the following: FeCl₃ 640 mg L^?1, cactus dosage 160 mg L^?1, and pH 6.0. Investigation of the effects of the storage time and temperature of the cactus O. ficus-indica showed that coagulation efficiency was not significantly affected for storage at room temperature for up to 4 days.     

Considerations about the land use and conversion trends in the savanna environments of Central Brazil under a geomorphological perspective

Assuming that the landscape physiographic characteristics strongly determine the occurrence of land use and land cover types, this study assessed the distribution patterns of natural and converted classes in relation to the major geomorphological units and slope ranges in the central area of continuous savanna formations in Brazil (Cerrado biome), the country’s most important region for cattle ranching and intensive commodity crops. Our results showed that 93% of the agriculture activities are concentrated at slopes of less than 5°, mostly associated to old regional planation surfaces (RPSs). Considering the amount of remnant vegetation and the occupation and land use deterministic trends, we estimated that between 58,041 km² and 79,677 km² of conversions may occur in the near future. If the priority areas for biodiversity conservation are properly enforced and effectively incorporated into the system of fully protected areas and areas of sustainable use, a decrease of approximately 24% in the expected potential deforestation could be achieved.     

Experimental and numerical study on the shear velocity distribution along one or two dunes in tandem

This paper investigates, experimentally and numerically, the shear velocity distribution along a single transverse dune and along two closely spaced dunes, analyzing the flow effects of one dune upon the other. The paper focuses on two-dimensional models simulating transverse sand dunes. The shape of the two pile geometries studied is described by sinusoidal curves, one having a maximum slope of $32^{\circ }$ and the other $27.6^{\circ }$ , with leeward flow separation. The tests were carried out for two undisturbed wind speeds and the experimental data obtained through wind-tunnel modeling encompass flow visualization and shear-velocity results. A generally good agreement is observed between the experimental measurements and computational results. From the inquiry between shear velocity distributions and published eroded contours for the same geometries, it appears the Bagnold’s approach is insufficient in the prediction of threshold conditions in wake flows formed in the dune’s leeward side.     

Occurrence of tar balls on the beaches of Fernando de Noronha Island,South Equatorial Atlantic

This work reports on the widespread occurrence of tar balls on a pebble beach of Sueste Bay on Fernando de Noronha Island, a Brazilian national marine park and a preserve in the South Equatorial Atlantic. Environmental regulations preclude regular visitors to the Sueste Bay beach, and the bay is a pristine area without any possible or potential sources of petroleum in the coastal zone. In this work, these tar balls were observed for the first time as they occurred as envelopes around beach pebbles. They are black in color, very hard, have a shell and coral fragment armor, and range in average size from 2 to 6 cm. The shape of the majority of the tar balls is spherical, but some can also be flattened ellipsoids. The polycyclic aromatic hydrocarbon analyses of the collected samples revealed the characteristics of a strongly weathered material, where only the most persistent compounds were detected: chrysene, benzo(b,k)fluoranthene, dibenzo(a,h)antracene and benzo(a)pyrene.     

Thermoplasticized Pectin by Extrusion/Thermo-Compression for Film Industrial Application

Journal of Polymers and the Environment - Researches for the development of materials with less environmental impact have been more common. Pectin is a natural polysaccharide, presenting in plants...     

Biogeochemical characterization of surface waters in the Aljustrel mining area (South Portugal)

Aljustrel mining area (South Portugal) is a part of the Iberian Pyrite Belt and encloses six sulfide mineral masses. This mine is classified of high environmental risk due to the large tailings’ volume and acid mine drainage (AMD)-affected waters generated by sulfides’ oxidation. The use of biological indicators (e.g., diatoms) revealed to be an important tool to address the degree of AMD contamination in waters. Multivariate analysis has been used as a relevant approach for the characterization of AMD processes. Cluster analysis was used to integrate the significant amount and diversity of variables (physicochemical and biological), discriminating the different types of waters, characterized by the high complexity occurring in this region. The distinction of two main marked phenomena was achieved: (1) the circumneutral-Na-Cl water type (sites DA, PF, BX, BF, RO, CB), expressing the geological contributions of the Cenozoic sediments of Sado river basin, with high diatom diversity (predominating brackish diatoms as Entomoneis alata); and (2) the acid–metal-sulfated water type (sites BM, JU, RJ, AA, MR, BE, PC, AF), reflecting both the AMD contamination and the dissolution of minerals (e.g., silicates) from the hosting rocks, potentiated by the extremely low pH. This last group of sites showed lower diatom diversity but with typical diatoms from acid- and metal-contaminated waters (e.g., Pinnularia aljustrelica). In addition to these two water types, this hierarchical classification method also allowed to distinguish individual cases in subclusters, for example, treated dams (DC, DD), with alkaline substances (lime/limestone), that changed the physicochemical dynamics of the contaminated waters.

     

Mercury in the Moji-Guaçu river basin,S.P-Brazil: the link between marginal lagoons and river contribution,assessed by 210Pb dating profiles

Total mercury content was evaluated in water and suspended sediment samples of the Moji-Gua?u river and in water and bottom sediment of its 3 marginal lagoons (Catingueiro, Barrinha, and Rio das Pedras), located downstream of the sampling point in the main channel. In all situations, low Hg concentrations were found in suspended and bottom sediments. Aluminum was used as a geochemical tracer to normalize the Hg concentrations in the sediment cores from the Rio das Pedras lagoon (r = 0.92). It was estimated that the Moji-Gua?u river transports up to 19 kg Hg yr(-1), 65% in the dissolved form and 35% adsorbed onto particulate matter. Following an acute toxic stage observed in the years 1970-1980, the basin has been restored to its original conditions mainly by natural recovery and a general reduction in Hg input to the ecosystem.