The authors are grateful to the Coordination of Improvement of
Higher Education Personnel (CAPES, Brazil) (CAPES-PRINT, Project

number 88887.310560/2018-00); to National Council for Scientific
and Technological Development (CNPq, Brazil) by the financial sup-
port (CNPq, 405965/2016-8); and to Coordination of Improvement of

Higher Education Personnel (CAPES, Brazil) by the scholarship (001)

The combined use of progressive and block freeze concentration in lactose-free milk: Effect of process parameters and influence on the content of carbohydrates and proteins

Wet washing is a widely used method for biodiesel purification. However, this technique generates a large amount of wastewater that needs to be treated afterward, which is costly and time-consuming. Thus, solvent-aided crystallization (SAC) with ultrasonic irradiation as solution movement assistance was introduced. This technique is based on the addition of 1-butanol to biodiesel to enhance purification via crystallization. During crystallization, two phases are formed, where glycerol solidifies (solid phase) and pure biodiesel remains (liquid phase). Technically, the implementation of ultrasonic technology can optimize laboratory work by saving time, as no cleaning or washing of the propeller is needed. Biodiesel purity was analyzed using gas chromatography-mass spectroscopy (GC-MS), where a purity of 99% was achieved. The optimum parameters in achieving higher purity fatty acid methyl ester (FAME) were a 1-butanol concentration of 1 wt.%, a coolant temperature of 9 °C, and a crystallization time of 40 min.

https://www.mdpi.com/2073-4352/11/2/212/pdf

Biodiesel Purification via Ultrasonic-Assisted Solvent-Aided Crystallization

The solubility of 1,4-dicyanobenzene (DCB) in 17 neat solvents, that is, methanol, ethanol, n-propanol, isopropanol, acetone, ethyl acetate, ethyl formate, methyl acetate, cyclohexanone, cyclopenta...

Determination, Correlation, and Thermodynamic Analysis of the Solid–Liquid Phase Equilibrium of 1,4-Dicyanobenzene in Pure Solvents at Various Temperatures

At present, biodiesel is known as an alternative fuel globally. It is also known that the purification of biodiesel before consumption is mandatory to comply with international standards. Commonly, purification using water washing generates a massive amount of wastewater with a high content of organic compounds that can harm the environment. Therefore, this study applied and tested a waterless method, i.e., the solvent-aided crystallization (SAC), to remove glycerol and other traces of impurities in the crude biodiesel. The parameters of coolant temperature, crystallization time, and stirring rate on the SAC system were investigated. It was discovered that with 14 °C coolant temperature, 300 RPM and higher cooling time result in the highest percentage of FAME up to 99.54%, which indicates that contaminants' presence is limited in the purified biodiesel. The use of 1-butanol as the solvent for crystallization process remarkably enhanced the separation and improved the higher biodiesel quality.

/pdf/parametric-study-of-glycerol-and-contaminants-removal-from-444rc61v86.pdf

Parametric study of glycerol and contaminants removal from biodiesel through solvent-aided crystallization

After the transesterification process is completed, the resulting product, crude biodiesel, contains different impurities such as free fatty acids, soap, excess methanol, catalyst, triglycerides, impurities from the raw material, glycerol, etc. To use biodiesel as a fuel, these impurities must be removed to the greatest extent. Many different technologies can be applied for that purpose, like gravitational settling, wet and dry washing, membrane separation, etc. The selection of the method used for purification depends on not only the feedstock used and conditions of the transesterification process but also desired purity of the biodiesel. Usually, a combination of methods is necessary to obtain biodiesel that meets the standards proposed by ASTM D6571 or EN14214. In this chapter, different purification technologies are reviewed and compared. Also, the challenges needed to overcome the existing limitations are critically discussed. 

Biodiesel purification: real-world examples, case studies, and current limitations

The application of solvent-aided crystallization (SAC) is based on the addition of a solvent, here 1-butanol, to crude biodiesel to catalyze the purification process by separating biodiesel from contaminants via crystallization process. Response surface methodology was applied to optimize the process parameters of SAC, represented by biodiesel purity. The purified biodiesel was analyzed by means of gas chromatography-mass spectrometry for the composition of the present fatty acid methyl ester (FAME). Under the predicted optimum process conditions within the experimental ranges for the highest biodiesel purity, the predicted biodiesel purity was 99.375 . Â© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

/pdf/solvent-aided-crystallization-for-biodiesel-purification-19hvovceee.pdf

Solvent‐Aided Crystallization for Biodiesel Purification

Treatment and disposal are two main approaches for water cycle management in the oil and gas industry. Freeze concentration has been identified as one of the methods to separate water from wastewater samples. The conventional method used for solution movement in progressive freezing technique is stirring by a stirrer. However, the stirrer requires frequent maintenance as it needs to be cleaned and requires longer cleaning time due to the complex structure of a stirrer. Thus, the new solution movement for progressive freezing is proposed, which is circular moving progressive freezing. This study aims to remove water from the wastewater sample (i.e., produced water). To optimize and investigate the effect of coolant temperature, freezing time and rotation speed, response surface methodology (RSM) was applied to determine the efficiency of the process and central composite design (CCD) was used to design the experiment. From the results, the optimum parameters were determined at the freezing time of 22.79 min, coolant temperature of −14.89 °C and rotation speed of 59 rpm. To evaluate the accuracy of the optimization process, a validation experiment was performed and water removal value of 89.67% was achieved.

Optimization of progressive freezing on synthetic produced water by circular moving cylindrical crystallizer via Response Surface Methodology

Recent studies have shown great interest toward heavy metal removal due to its hazardous and non-biodegradable properties. Many approaches have been used for this purpose and one of them is adsorption. In this study, several experiments were carried out to investigate the feasibility of factory tea waste as a biosorbent in a fixed-bed adsorption column for heavy metal removal (zinc and copper) in wastewater. The results highlighted that zinc has better performance compared to copper in terms of the effect of initial ion concentration, pH value, and the mixed ions with respect to the removal efficiency. Zinc showed higher removal efficiency and adsorption capacity at the initial metal ion concentration of 200 mg/L, which are 99.21% and 39.68 mg/mg compared to copper. Meanwhile, for the effect of pH values and mixed ion concentration, zinc also showed slightly higher removal efficiency which are 99.91% and 98.47%, respectively compared to copper. However, both zinc and copper showed a better fit to the Langmuir isotherm. The factory tea waste was characterized using Micromeritics ASAP 2020 instrument and results showed that the factory tea waste biosorbent consists of mesopores with the diameter and width of 4.85205 and 2.546985 nm, respectively.

/pdf/factory-tea-waste-biosorbent-for-cu-ii-and-zn-ii-removal-35h89zmwe4.pdf

Eduard Hernández Yáñez

Papers

Solvent‐Aided Crystallization for Biodiesel Purification

Optimization of progressive freezing on synthetic produced water by circular moving cylindrical crystallizer via Response Surface Methodology

Factory Tea Waste Biosorbent for Cu(II) and Zn(II) Removal from Wastewater