Biochars from animal wastes as alternative materials to treat colored effluents containing Basic Red 9

Bovine bones (BB) and fish scales (FS) were used as alternative precursors to produce biochars, which in turn, were applied for the removal of Basic Red 9 (BR9) from aqueous solutions. BB and FS were pyrolyzed generating a solid (biochars), a liquid (pyrolytic oils) and a gas fraction. All fractions were characterized to evaluate the pyrolysis process. The biochars presented different functional groups and a mesoporous structure with surface areas around 90 m2 g–1. Both biochars demonstrated potential to adsorb BR9, with maximum adsorption capacities of 49.5 (BB–biochar) and 52.3 mg g–1 (FS–biochar). Pyrolytic oils were composed mainly by palmitic acid (BB) and imidazolidinedione (FS), which are compounds with biological and antioxidant activity. Pyrolysis of BB generated CO2 while pyrolysis of FS generated H2. In summary, bovine bones and fish scales are promising precursors to concomitantly produce biochars with great adsorbent potential and oils with interesting characteristics

Treatment of residual lubricating oil using rice husk-based material as ecological adsorbent

One of the most significant environmental problems the world population faces is the inadequate disposal of petroleum derivatives. Lubricant oil is a hazardous waste due to its properties and characteristics. This study is a new proposal for using rice waste as an adsorbent to remove lubricating oils from a water medium. Rice husk from local industries was prepared using four different techniques: thermal treatment, alkaline treatment, acid treated and without treatment. The experiment used a mineral-based lubricating oil for gasoline and ethanol engines as adsorbate. Absorbents were characterized using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), morphological structure (SEM), energy-dispersive spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) analysis. Specific surface area and pore size distribution (BET/BJH). The adsorbent without treatment showed the smallest surface area (0.79 m2 g−1), while the adsorbent produced using acid treatment showed the largest (3.71 m2 g−1). The adsorption kinetic behavior was obtained by adjusting the pseudo-first-order, pseudo-second-order, and Elovich models. Elovich models showed more adequate results to represent the kinetic profile. The adsorbents showed high adsorption capacities, ranging from 1650 to 2000 mg g−1. The adsorbent produced using heat treatment (RH-H) was the most efficient for removing lubricating oil

Biosorption of Metals and Metalloids

Industrial activities such as mining operations, refining of ores and combustion of fuel oils play a relevant role in environmental pollution since their wastes contain high concentrations of toxic metals that can add significant contamination to natural water and other water sources if no decontamination is previously applied. As toxic metals and metalloids, including arsenic, cadmium, lead, mercury, thallium, vanadium, among others, are not biodegradable and tend to accumulate in living organisms, it is necessary to treat the contaminated industrial wastewaters prior to their discharge into the water bodies. There are different remediation techniques that have been developed to solve elemental pollution, but biosorption has arisen as a promising clean-up and low-cost biotechnology. Biosorption is one of the pillars of bioremediation and is governed by a variety of mechanisms, including chemical binding, ion exchange,physisorption, precipitation, and oxide-reduction. This involves operations(e.g. biosorbent reuse, immobilization, direct analysis of sample without destruction) that can be designed to minimize or avoid the use or generation of hazardous substances that have a negative impact on the environment and biota, thus following the concepts of "green chemistry" and promoting the environmental care. Furthermore, it has to be specially considered that the design of a biosorption process and the quality of a biosorbent are normally evaluated from the equilibrium, thermodynamic, and kinetic viewpoints.Therefore, a successful biosorption process can be only developed based on multidisciplinary knowledge that includes physical chemistry, biochemistryand technology, among other fields.In this chapter, we explain in detail all the aforementioned aspects. State of the art applications of biosorbents for metals and metalloids removal are carefully revised based on a complete analysis of the literature. Thus, it is evidenced in this chapter that the main points to consider regarding biosorption are the type of biomaterial (e.g. bacteria, fungi, algae, plant?derivatives and agricultural wastes, chitin/chitosan based materials) and the presence of a broad set of functional groups on their surface that are effective for the removal of different toxic metals and metalloids. In fact, removal percentages as high as 70-100% can be found in most works reported in the literature, which is demonstrating the excellent performance obtained with biosorbents. Also, biosorbents have evolved with the help of nanotechnology to modern bio-nano-hybrids materials having superlative sorption properties due to their high surface area coming from the nano-materials structures and multifunctional capacity incorporated from the several types of chemical groups of biomaterials. These, as well as other important aspects linked to biosorption are fully covered in the present chapter.Fil: Escudero, Leticia Belén. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Quintas, Pamela Yanina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Wuilloud, Rodolfo German. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Dotto, Guilherme L.. Universidade Federal de Santa Maria; Brasi