Propuesta de administración y operación del núcleo forestal productivo de guadua en la zona urbana del municipio de Pereira departamento de Risaralda

Actualmente el paisaje predominante en el eje cafetero corresponde a una gran matriz agrícola, donde predominan las pasturas con pequeños fragmentos con Guadua angustifolia Kunth que se caracteriza por tener una composición florística donde convive la guadua con otras especies. Se observa la presencia cada vez más abundante de condominios campestres que rodean las principales ciudades de la región y que denotan la dinámica de expansión urbana. (GATA, 2016). Los habitantes del municipio de Pereira reconocen desde tiempos ancestrales la importancia de los guaduales como sitios que brindan esparcimiento, ayudan a la regulación de cauces y proveen de materiales resistentes, además de que son de rápido crecimiento. En Colombia el uso de la guadua para construcción, data desde el siglo XIX cuando se empezó a producir la denominada colonización antioqueña, desde allí se dio inicio a la edificación de aldeas, barrios y hasta ciudades. Gracias a sus excelentes comportamientos tanto a flexión, compresión y tracción, la Guadua se ha utilizado en innumerables edificaciones que han dado progreso y desarrollo a los pueblos colombianos

Uticaj hloridnih jona na elektrohemijsku oksidaciju cijanida u otpadnim vodama

The paper describes the influence of chloride ions on the electrochemical oxidation of cyanide from wastewater. Chloride ions are added in the form of NaCl (c=0.017 mol/L), and electrochemical oxidation is carried out in a laboratory electrochemical reactor with electrodes made of steel and stainless steel (j=10 mA/cm2, t=90 min). In these conditions the removal efficiency of cyanide on steel electrodes was Eu = 91.5%, and with electrodes made of stainless steel Eu = 99.5%.U radu je prikazan uticaj hloridnih jona na elektrohemijsku oksidaciju cijanida iz otpadnih voda. Hloridni joni su dodavani u obliku NaCl (c=0,017 mol/L), a elektrohemijska oksidacija je vršena u laboratorijskom elektrohemijskom reaktoru sa elektrodama od čelika i nerđajućeg čelika (j=10 mA/cm2, t=90 min.). Pri navedenim uslovima efikasnost uklanjanja cijanida na čeličnim elektrodama je bila Eu=91,5%, a sa elektrodama od nerđajućeg čelika Eu=99,5%

UTICAJ ELEKTRODNOG MATERIJALA NA ANODNU OKSIDACIJU CIJANIDNIH OTPADNIH VODA

Anodna oksidacija je elektrolitička elektrodna reakcija. Ovim postupkom se uspješno vrši oksidacija cijanidnih otpadnih voda. Anodna oksidacija cijanida zavisi od gustine struje, sastava rastvora, radne temperature itd., a najviše od elektrodnog materijala. Cijanidi su veoma reaktivna jedinjenja koja u obliku cijanovodonika (HCN) predstavljaju izuzetno smrtonosan gas u vlažnim i kiselim uslovima. Pored toga, velika količina cijanida se koristi u rudarstvu, metalo-prerađivačkoj i elektronskoj industriji. Budući da su cijanidi vrlo reaktivani, lako se vežu za metal kao ligand u obliku kompleksa različite stabilnosti i toksičnosti. Budući da ta jedinjenja mogu izazvati veliku štetu za ljude i organizme ako dođu u zemljište i podzemne vode, otpad koji sadrži cijanide treba tretirati vrlo pažljivo za to pogodnim metodama

Combined analytical study on chemical transformations and detoxification of model phenolic pollutants during various advanced oxidation treatment processes

Advanced oxidation processes (AOPs) have been introduced to deal with different types of water pollution. They cause effective chemical destruction of pollutants, yet leading to a mixture of transformation by-products, rather than complete mineralization. Therefore, the aim of our study was to understand complex degradation processes induced by different AOPs from chemical and ecotoxicological point of view. Phenol, 2,4-dichlorophenol, and pentachlorophenol were used as model pollutants since they are still common industrial chemicals and thus encountered in the aquatic environment. A comprehensive study of efficiency of several AOPs was undertaken by using instrumental analyses along with ecotoxicological assessment. Four approaches were compared: ozonation, photocatalytic oxidation with immobilized nitrogen-doped TiO$_2$ thin films, the sequence of both, as well as electrooxidation on boron-doped diamond (BDD) and mixed metal oxide (MMO) anodes. The monitored parameters were: removal of target phenols, dechlorination, transformation products, and ecotoxicological impact. Therefore, HPLC–DAD, GC–MS, UHPLC–MS/MS, ion chromatography, and 48 h inhibition tests on Daphnia magna were applied. In addition, pH and total organic carbon (TOC) were measured. Results show that ozonation provides by far the most suitable pattern of degradation accompanied by rapid detoxification. In contrast, photocatalysis was found to be slow and mild, marked by the accumulation of aromatic products. Preozonation reinforces the photocatalytic process. Regarding the electrooxidations, BDD is more effective than MMO, while the degradation pattern and transformation products formed depend on supporting electrolyte

Electrochemical treatment of wastewater to remove contaminants from the production and disposal of plastics

Wastewater is major source of contaminants originating from the production, usage, and disposal of plastic materials. Due to their poor biodegradability of these contaminants in municipal wastewater treatment plants, additional advanced oxidation processes such as electrochemical treatments have been developed to improve the standard biological treatment. Here we review the applications of electrochemical treatments of wastewater for the removal of the following plastic contaminants: bisphenol A, phthalic acid esters, and benzotriazoles. We present the effectiveness of treatment in terms of contaminant removal and mineralizationthe identification of transformation productstoxicity assessmentand process energy requirements. In the present review, we have focused on the applications of electrochemical treatments of wastewater for the removal of three important groups of contaminants originating mainly from plastics: bisphenol A, phthalic acid esters, and benzotriazoles. The review focuses on the research of electrochemical treatments for these contaminants from the last five years. The papers are assessed from the point of i) effectiveness of treatment in terms of contaminant removal and mineralizationii) identification of transformation productsiii) toxicity assessmentiv) processes’ energy requirements. Electrochemical treatments were confirmed to be a viable option for the removal of selected contaminants from wastewater

Electrooxidation of polar benzotriazole - The impact of supporting electrolyte

Polar benzotriazoles are heterocyclic compounds widely used in industry, and as such are easily released into the environment. These compounds show harmful and toxic effects on plants and some aquatic organisms, biodegrade quite slowly, and some, depending on the structure, have the ability to bioaccumulate. They can only be partially removed by conventional wastewater treatment, and are therefore found in a variety of waters, as well as solid waste. In this paper, synthetic wastewater containing polar benzotriazole was treated by an electrooxidation process. The efficiency of the treatment was tested depending on various parameters, such as: anode material (mixed metal oxide - MMO and boron-doped diamond - BDD), applied current density (10 and 20 mA/cm2), type of supporting electrolyte (NaCl, Na2CO3, Na2SO4, H2SO4) and treatment time (0.5 - 2.5 h). Obtained results showed the treatment was more effective at higher current density and by using BDD anode. Also, the efficiency of the treatment increases with the prolongation of the electrolysis time. After 2.5 h of treatment, 97.9% of benzotriazole was removed, in the presence of sulfuric acid as supporting electrolyte

Electroconductive copper powder filled PMMA composites

This article is concerned with synthesis and characterization of electroconductive composite materials prepared by hot molding of mixtures of PMMA and electrochemically deposited copper powder and investigation of the influence of particle morphology on conductivity and percolation threshold of obtained composites and thermal characteristics. Electrodeposited copper powder content was varied from 0.5-8.8 vol%. Analysis of the most significant properties of individual components and prepared composites AFM and TGA analysis. The significant increase of the electrical conductivity can be observed as the copper powder content reaches the percolation threshold at 2.98 vol%. In the investigated range of electrodeposited copper powder concentrations the increase of the electrical conductivity of composites is as much as sixteen orders of magnitude

Advanced treatments for the removal of alkylphenols and akylphenol polyethoxylates from wastewater

International audienceSince the 2000s, among organic contaminants, alkylphenols and alkylphenol polyethoxylates have been listed as hazardous substances by several national, European and international agencies because they are considered endocrine disruptors. Among the molecules classified as priority substances in terms for monitoring and action, nonylphenols and octylphenols and their polyethoxylated derivatives receive particular attention, especially in developing countries. Effluents from treatments plants are considered to be the largest source of alkylphenols in the environment. Although legislation concerning their use has become increasingly strict, these substances are still found in the environment, especially in water resources. The existing water and wastewater treatment plants have not been designated for these emerging contaminants. Conventional treatments such as biodegradation, sand filtration, carbon adsorption and/or chemical oxidation in place are not effective in their elimination removal. No appropriate methods have been developed to deal them at the urban or industrial scale. Thus, alkylphenols have become a relevant research topic for scientists interested in water engineering issues related to their treatment. However, the challenge is not simple, as it is difficult to remove trace contaminants from complex mixtures of substances in a way that is chemically effective, technologically simple, economically viable, and environmentally friendly.The main objective of this chapter is to summarize recent trends in proposed advanced treatment methods for the removal of alkylphenols and alkylphenol polyethoxylates from wastewater. After general and brief considerations on these emergingcontaminants, this chapter focuses on adsorption-oriented processes, biotechnological methods, and advanced oxidation processes. Among the advanced methods described and discussed are removal of alkylphenols and alkylphenol polyethoxylates by adsorption onto cyclodextrin polymers, clays or molecularly imprinted polymer, biodegradation using microalgae or constructed wetlands or by sequential anaerobic-aerobic digestion processes, treatments based on ozone-carbon coupling, electrochemical degradation, photocatalysis, zero-valent iron-activated persulfate coupling and catalytic ozonation. Among these technologies, advanced oxidation processes, in association with biodegradation and/or adsorption, seem to be the technique of the future, although their costs still prevent their widespread use