Pigments from natural sources, such as bacterial pigments, have gained increased attention in recent years due to their biodegradability, non-toxicity, and noncarcinogenicity. The intention to replace synthetic and oil-derived compounds is not restricted to synthetic dyes; other applications include the replacement of oilderived polymers for more environmentally friendly options, such as biopolymers. In this work, the functionalization of a bacterial cellulose (BC) biopolymer with bacterial pigments was explored using a full factorial design methodology to evaluate the best functionalization conditions to produce colored BC. From the factors and interactions evaluated, it was possible to conclude that the variable duration of the functionalization procedure could be reduced to a low level without significantly affecting the functionalization of the BC samples with bacterial pigments. Moreover, BC is a product with high industrial applicability, versatility, and sustainability. Hence, the multifunctional colored BC can be applied in the packaging, paper, and textile industries, among others. Keywords: bacterial pigments, bacterial cellulose, full-factorial design, optimization
LaTi1−xFexO3 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) perovskite-type oxide samples were synthesized by the solid state reaction method and characterized, and their photocatalytic activity was tested in the degradation of Acid Orange 7 under ultraviolet and visible light. The oxides were successfully synthesized and the XRD results showed a phase change from monoclinic to orthorhombic, with an increase in Fe content (x), with LaTi0.8Fe0.2O3 and LaTi0.6Fe0.4O3 samples presenting both phases. All samples presented low photocatalytic activity under visible light radiation, with a maximum Abs484nm removal of 2.9% for LaFeO3 after one hour. The best results were obtained under ultraviolet radiation, for all samples, with the best photocatalytic activity exhibited by the La2Ti2O7 perovskite, with 44.6% Abs484nm removal after one hour. Keywords: perovskites, LaTi1−xFexO3, photocatalysis, Acid Orange 7
Due to the negative effects of its main inflows, the water quality of Roxo stream, located in southern Portugal, an area characterized by Mediterranean climate, is degraded, causing consequences in irrigated agricultural activity. The eco technology of floating beds was used to improve the quality of this water. Three Vetiver zizinioides floating beds (3.3 m2/unit; density 40.5 plants/m2) were placed on the Roxo stream in May 2020 and the water quality was monitored until December 2020 in two places: at the floating beds location and 100 m higher up in the stream. The load mass was calculated for both sampling points and the removal rate for each parameter was monitored. The average removal rates obtained were: (i) TN = 33%; (ii) TP = 43%; (iii) COD = 44%; and (iv) Cl- = 15%. The DO level increased slightly, and the pH remained neutral. Although the water quality improved, the quality was still not high enough to be able to use the water for irrigation and to achieve good ecological status. Keywords: Roxo stream, surface water quality, real scale, floating beds, Vetiver zizinioides
Two potential measures for increasing water use efficiency in a municipal sports center were evaluated: (1) the reuse of water originating from showers in the flushing toilets in the indoor football court building; and (2) the reuse of water from swimming pool filter backwashing for irrigation. In the indoor football court building the total annual water consumption is around 3,500.5 m3 and from the showers is approximately 1,785.26 m3. Therefore, the greywater generated in showers can be reused in toilet flushing, which consumes about 840.12 m3 per year. The estimated annual water consumption for filter backwashing is 4,197.6 m3. The annual amount of water necessary for irrigating the lawn of the local football stadium is around 7,200 m³. Thus, the filter backwashed water, after being subjected to a sedimentation process, could be fully reused for this purpose. Keywords: water efficiency, water reuse, swimming pools filter backwashing reuse, sports center, sustainability
High consumption of clean water results in the generation of effluents that need to be treated and then safely discarded. Conventional methods for such treatment often do not offer an economical and sustainable result; therefore, new methods are needed, such as microalgae usage. Microalgae are unicellular beings capable of rapid adaptation, growth, and production of compounds of interest (pharmaceuticals, biofuels and others). This work aimed to study the effectiveness of the microalgae Selenastrum sp. in the treatment of effluents from the textile and pulp & paper industries, as well as the respective effects on its biomass development and accumulation of compounds. Four types of culture were carried out (for each type of effluent, a control, and a control with addition of glucose) lasting eight days, in duplicate, all with the addition of a standard culture medium and controlled abiotic factors. Analyses for compound removal (chemical oxygen demand and colour readings on the 200–800nm range) and biomass development (cell number, its dimensions, and weight) were performed four times during the process. At the end of the experiments, the average removal in effluents for COD and colour were 56.6% and 32.7% respectively, in addition to a biomass accumulation of 0.45 g/L. These results were comparable to those obtained for the control cultivation using glucose as a carbon source (70.0% COD removal and 0.51 g/L biomass accumulation). These results demonstrate the effectiveness of Selenastrum sp. in the treatment of industrial effluents, its resilience in stressful environments and the potential use of its accumulated compounds for biotechnological purposes. Keywords: microalgae, Selenastrum sp., industrial effluent, textile effluent, pulp effluent, effluent treatment
