The manufacture of leather covers a wide productive chain and beyond contributes to the economic flow. The various stages of leather processing result in high volumes of solid waste. In Brazil, a daily generation of 375 tons of solid waste is estimated, and landfills are still the most used route to its destination. In this review, emphasis will be given to researches that have sought alternatives for the use of solid waste from the tannery industry. Among the main applications of solid tannery wastes, the following stand out production of adsorbent materials, biodiesel, biogas, biopolymers, applications in agriculture and other applications involving extraction/recovery of compounds of industrial/commercial interest, isolation of microorganisms and production of enzymes and applications in the animal diet. In each alternative of waste application, the technologies used, the opportunities, and the challenges faced are mentioned. We hope that this review can provide valuable information to promote the broad understanding of the possibilities that tannery solid wastes has for the development of biodegradable and agricultural products, wastewater treatment, extraction of compounds of industrial and commercial interest, among others.
The overuse of polymer materials from fossil sources has generated a large volume of waste that causes environmental impacts due to the degradation time. The technological advance has stimulated the search for alternatives that can contribute to sustainability. In this context, the use of biodegradable polymers, that use raw materials from renewable sources stand out because they have that ability to form films and come from abundant sources. Also, in the expectation of optimizing the environmental benefits in this process, it is possible to value the agroindustrial residues, using them as raw material in the synthesis of the polymer, the physical, chemical and mechanical properties of these polymers are important to evaluate the possible applications. The proposal of this chapter is to present current research on renewable sources, including agricultural and industrial residues, to obtain biodegradable polymers, highlighting their properties and possibilities of application.
The textile industries are responsible for generating large volumes of effluents containing toxic dyes, harmful to ecosystems if disposed of without prior treatment. The adsorption process stands out due to its simplicity and efficiency in removing a wide variety of contaminants present in effluents, also, it allows the use of residual biomass from agriculture. The soybean hull is a by-product of wide available but made used only for animal feed. Thus, the present study aimed to characterize and evaluate the soybean husk as a biosorbent of the 5G blue reactive dye, widely used in the dyeing processes of the textile industries. The soybean hull was characterized by SEM and FTIR. Kinetic and equilibrium tests were carried out under conditions of pH 2, 40 ºC, and 90 rpm. Besides, kinetic and equilibrium mathematical models previously described in the literature were adjusted to the experimental data. Through the morphological characterization of the biosorbent, it was possible to evidence superficial pores in practically all their extension, a characteristic that directly influences the adsorption process. The analysis of FTIR showed, as expected, the presence of functional groups characteristic of lignocellulosic substances. Besides, the results obtained in the kinetic and equilibrium essays in the studied conditions show that the adsorption equilibrium was obtained in about 120 min, with the removal of 88% of the dye. The mathematical modeling indicated that the pseudo-second order and Sips models were the most adequate to represent the kinetic and equilibrium experimental data, respectively. The maximum adsorption capacities calculated experimentally and predicted by the Sips model were 53.33 and 48.13 mg g -1 , respectively. In general, the biosorbent studied was effective to remove the reactive dye.
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