Evaluation in vivo and in vitro of the extracellular products (ECP) of a group of Renibacterium salmoninarum strains from different geographic origins revealed a low production of extracellular proteins in all strains and confirmed that most of the isolates were poor producers of proteolytic enzymes. The ECP displayed neither haemolytic activity nor capacity to alter the osmotic equilibrium of fish erythrocytes. In addition, none of the ECP samples displayed cytotoxic activities regardless of the origin of the cell line employed and did not contain substances lethal for fish, since no mortalities were recorded when doses ranging from 10 to 20 μg protein/g fish were administered. Although the present work failed to demonstrate toxicity in vivo of the ECP, it is possible that some extracellular enzymes contribute to the weakening of fish during the disease process and allow bacterial survival.

O presente artigo tem como objetivo difundir os fundamentos teóricos-conceituais sobre a temática das matas ciliares e rios urbanos, trazendo suas funções dentro do ambiente e aparatos da legislação federal que versam sobre essas áreas em questão. Dentro dos inúmeros conceitos, a vegetação situada próxima aos cursos d’água denominada de mata ciliar, são consideradas como os cílios das águas e agem como protetora desses ambientes. As matas ciliares são ainda definidas como formações vegetais extremamente importantes para o desenvolvimento dos processos ambientais e por isso são protegidas pela Lei federal N° 12651/12 nomeada de Lei do Código Florestal. Os rios urbanos são mananciais que tiveram grandes centros urbanos desenvolvidos no seu entorno, e são caracterizados como importantes corredores biológicos que permitem a presença da flora e da fauna nas cidades e formam as bacias hidrográficas. Quanto à legislação vigente federal acerca das áreas de mata ciliar urbana, identifica-se que há um compromisso governamental presente, inclusive com a implementação da Lei 14285/21 que altera a lei marco do Código Florestal em relação no tocante a municipalização das regras de APP’s urbanas. Conclui-se ainda que há um compromisso governamental presente com objetivos de regular das formas de uso e ocupação nas áreas protegidas e que estas leis, se colocadas em práticas de forma integrada, são deveras capazes de conferir uma ampla faixa de proteção a essas áreas ambientais.

In this study, four types of “Juá” stem barks (Ziziphus joazeiro) were investigated for the removal of Cu(II) from aqueous solutions. The tested samples included natural coarse barks, and barks washed with water, ethanol–water, and NaOH solutions. The solvent-modified materials simulated the waste of the industrial extraction of saponins from bark. The valorization of these processing residues as sorbents was evaluated. The NaOH-washed sorbent exhibited the highest sorption capacity for Cu(II) (maximum sorption capacity $$\approx$$≈ 32 mg g⁻¹). Ion exchange process between copper and exchangeable surface cations and electrostatic attraction of copper with carboxylate and phenolate groups were identified as the primary sorption mechanisms. Desorption tests revealed that a large portion of the metal sorbed (80%) was easily released from the sorbent thus suggesting, in line with the proposed mechanisms, the existence of weak sorbate-sorbent interactions. The sorptive process was found to be exothermic (∆H° = − 48.1 ± 13.5 kJ.mol⁻¹) and thermodynamically favorable at lower temperatures. Graphical Abstract

In this study, five types of modified Ziziphus joazeiro barks were investigated for the removal of Pb(II) ions from aqueous solutions. The samples tested were natural barks, natural powder, washed with water, ethanol at 80% (EE) and 0.5 N NaOH. Batch kinetics experiments were performed under the conditions: 24–25 °C, pH 5.5–5.8, 102 mg·L⁻¹ Pb(NO₃)₂, 100 rpm and 0.1 g of adsorbent, and analyses of pHpzc and Fourier transform infrared spectroscopy. All adsorbents tested showed potential to remove Pb(II) ions, but the adsorbent washed by 0.5 N NaOH obtained the highest experimental performance (25.5 mg·g⁻¹ at 30 min), while the EE had the least performance (20.4 mg·g⁻¹ at 60 min), and maximum removals of 99.9%. The kinetic models pointed to a probable chemisorption due to the best fit of pseudo-second order and Elovich, and Boyd’s model, suggesting that intraparticle diffusion limits the adsorption until the initial minutes of contact. The Langmuir isotherm fitted better to the experimental data for the NaOH adsorbent, with maximum adsorption capacity equal to 62.5 mg·g⁻¹, although the Temkin model partially fitted, both suggesting the occurrence of chemisorption. The adsorption process is reversible (>81% at 20 min) and hence the adsorbents can be recycled and the Pb(II) ions recovered.

O objetivo desta pesquisa consiste na proposição de uma alternativa de tecnologia para a remoção de ferro e manganês em fontes de abastecimento público no município de Crato, Ceará, a partir da avaliação de parâmetros de qualidade de água atuais. A remoção desses compostos torna-se necessária haja vista os problemas associados a eles quando presentes em valores acima dos limites permissíveis. A concentração elevada provoca alterações físicas e químicas na água, como mudança de coloração e odor característico, levando a rejeição ao consumo da água. Diante disto, realizou-se análises físico-químicas em 35 pontos de abastecimento, escolhidos conforme critério de localização e existência de dados anteriores sobre sua qualidade organoléptica, a fim de identificar a concentração destes metais e propor um método compatível para sua remoção e controle eficiente. Para tanto, aplicou-se o teste de Wilcoxon, para avaliar o grau de dispersão dos dados em torno da média de concentração e em seguida ordenou os dados em faixas de concentração. A partir da análise dos resultados, foi recomendado oxidação por hipoclorito de cálcio seguida de filtração em leito de carvão ativado, por ser um dos processos mais eficientes de remoção dos compostos de ferro e manganês solúveis.

The aim of this study was to evaluate the efficiency of activated biochar produced from Moringa oleifera L. wood for removing azoxystrobin (fungicide) and deltamethrin (insecticide) from water. The adsorption of pesticides on activated carbon was studied using batch tests evaluating the influence of contact time (1–180 min), concentration (5–50 mg L⁻¹), and temperature (283, 298 and 313 K). The highest removal percentage obtained was 94.39% for azoxystrobin and 91.96% for deltamethrin, considering an initial concentration of 10 mg L⁻¹ and adsorbent dosage of 5.0 g L⁻¹. FTIR spectra confirmed H-bonding in the adsorption process, SEM analysis revealed homogeneous surface area characteristics, and BET results confirmed a highly superficial area for the activated carbon, all of which favor pesticide adsorption. The Boyd model showed that the intraparticle diffusion stage is determinant for both compounds in the initial stages of the adsorption process. The Sips model was the isotherm with the best fit to the experimental data, possibly indicating cooperativity between adsorbate molecules at low temperatures. The thermodynamic study showed a favorable adsorption at all the temperatures investigated, given the negative value of ΔG°. In addition, this study revealed good adsorption capacities for the material indicating that Moringa oleifera wood activated carbon is a viable alternative for removing azoxystrobin and deltamethrin from water.