Value-Added Utilization Processes of Industrial Wastes

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Environmental and Green Processes".

Deadline for manuscript submissions: closed (15 May 2023) | Viewed by 15129

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Guest Editor
Escola Superior de Biotecnologia, CBQF - Centro de Biotecnologia e Química Fina – Laboratório Associado, Universidade Católica Portuguesa, Porto, Portugal
Interests: biological valorization of wastes through the production of biopolymers; fractionation of wastes and purification of components to produce platform chemicals and functional ingredients; economic viability of waste valorization processes
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Special Issue Information

Dear Colleagues,

Valorization of industrial wastes and by-products is a current strong line of research. In recent decades, with the increasing environmental awareness, depletion of natural resources and the outbreak of the circular economy concept, the trend to manage industrial wastes has shifted from treatment for disposal to valorization, aiming to add value to waste and by-products stream by applying economically viable processes. Conventional waste valorization processes generally involve incineration for energy recovery and conversion to use in agriculture or animal feed or composting. This processing squanders the high potential of some industrial wastes though failing to exploit the vast diversity of molecules and functionalized chemical components available to be valorized as value-added products. Indeed, industrial wastes ought to be recognized as resources rather than wastes.

Novel processes and technologies are continuously emerging. This Special Issue on “Value-Added Utilization Processes of Industrial Wastes” aims to cover advanced and innovative processing technologies for industrial wastes valorization.

Topics include, but are not limited to:

  • Innovative processes for wastes valorization
  • Insights into developing potential processes for valorization of different wastes via chemical, thermal, biological, and electrochemical processes in order to obtain value-added products
  • Case studies of application of various waste valorization processes, focusing on the integration into current waste management systems

Dr. Catarina S.S. Oliveira
Guest Editor

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Keywords

  • Residues
  • Wastes
  • Added value products
  • Processes
  • Biorefinery
  • Materials
  • Chemical platform
  • Functional ingredients
  • Circular economy

Published Papers (7 papers)

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Research

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17 pages, 7869 KiB  
Article
Design of a RGB-Arduino Device for Monitoring Copper Recovery from PCBs
by Joan Morell, Antoni Escobet, Antonio David Dorado and Teresa Escobet
Processes 2023, 11(5), 1319; https://doi.org/10.3390/pr11051319 - 24 Apr 2023
Viewed by 1555
Abstract
The mobile phone industry, one of the fastest advancing sectors in production over the last few decades, has been associated with a high e-waste generation rate. Simultaneously, a high demand for the production of new electronic equipment has led to the scarcity of [...] Read more.
The mobile phone industry, one of the fastest advancing sectors in production over the last few decades, has been associated with a high e-waste generation rate. Simultaneously, a high demand for the production of new electronic equipment has led to the scarcity of certain metals. In this context, many recent studies have focused on recovering certain metals from e-waste through the use of bioprocesses. Such recovery processes are based on the action of microorganisms that produce Fe(III) as an oxidant, in order to leach the copper contained in printed circuit boards. During the oxidation-reduction reaction between Fe(III) and metallic Cu, the color of the solution evolves from an initial reddish color, due to Fe(III), to a bluish-green color, due to the oxidized Cu. In this work, a hardware-software prototype is developed, through which the concentrations of the key analytes—Fe(III) and Cu(II)—can be determined in real time by monitoring the color of the solution. This is achieved through the use of a non-invasive system, taking into account the aggressiveness of the solutions used for the bioprocessing of electronic components. In the work presented herein, the evolution of the solution color during the bioprocessing of two different types of waste (i.e., electric cable and mobile phones) is analyzed and then compared with the results obtained for pure metallic copper. The results are validated through comparison of the predicted results with the outcomes of conventional procedures, including offline sampling and analysis of Cu(II) and Fe(III) through atomic absorption and UV-VIS spectroscopy, respectively. The developed monitoring system allows an algorithm to be designed that can fit the evolution of analyte concentrations without the need for sampling or the use of complex, tedious, and expensive analytic techniques. It is also worth noting that the monitoring system is not in direct contact with the solution (which is highly aggressive for the processing of electronic equipment), making the system more durable than classic sensors that must be submerged in the solution. The real-time nature of the obtained information allows for the development of control actions and for corrective measures to be taken without affecting the biomass involved in the process. Full article
(This article belongs to the Special Issue Value-Added Utilization Processes of Industrial Wastes)
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11 pages, 2763 KiB  
Article
A Step for the Valorization of Spent Yeast through Production of Iron–Peptide Complexes—A Process Optimization Study
by Carlos Ferreira, Carla F. Pereira, Ana Sofia Oliveira, Margarida Faustino, Ana M. Pereira, Joana Durão, Joana Odila Pereira, Manuela E. Pintado and Ana P. Carvalho
Processes 2022, 10(8), 1464; https://doi.org/10.3390/pr10081464 - 26 Jul 2022
Cited by 3 | Viewed by 2575
Abstract
Given the importance of iron in human nutrition and the significance of waste and by-product valorisation in a circular economy environment, we investigated the effects of protein and iron concentration on the production yield of iron–peptide complexes from spent Saccharomyces cerevisiae. For [...] Read more.
Given the importance of iron in human nutrition and the significance of waste and by-product valorisation in a circular economy environment, we investigated the effects of protein and iron concentration on the production yield of iron–peptide complexes from spent Saccharomyces cerevisiae. For this purpose, different amounts of protein and iron were used in the complexation process. The results have shown that higher concentrations, although permitting a faster and larger scale process, provide a significantly lower complexation yield, which deems the process less feasible. This is corroborated by fluorescence analysis, which shows a lower degree of complexation with higher protein concentration. In addition, varying the concentration of iron does not change the quality of formed complexes, as evidenced by Fourier transform infrared spectroscopy (FT-IR) analysis. The morphology of all samples was also evaluated using scanning electron microscopy (SEM). Therefore, further studies are needed to optimize the process and to evaluate the best conditions for an economically sound valorization process for iron–peptide complexes. Nonetheless, current results in the development of a new process for the valorisation of spent yeast, in the form of iron-peptide complexes, look promising. Full article
(This article belongs to the Special Issue Value-Added Utilization Processes of Industrial Wastes)
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15 pages, 1185 KiB  
Article
Valorization of Spent Sugarcane Fermentation Broth as a Source of Phenolic Compounds
by Carla Maria Oliveira, Bruno Horta, Tânia Leal, Manuela Pintado and Catarina S. S. Oliveira
Processes 2022, 10(7), 1339; https://doi.org/10.3390/pr10071339 - 08 Jul 2022
Cited by 3 | Viewed by 1757
Abstract
A methodology based on a solid phase extraction (SPE) was optimized for the recovery of phenolic compounds from the spent fermentation broth generated from Biofene® (trans-β-farnesene) production. For this purpose, two resins (XAD-2 and HP-20) and three desorption solutions (water, [...] Read more.
A methodology based on a solid phase extraction (SPE) was optimized for the recovery of phenolic compounds from the spent fermentation broth generated from Biofene® (trans-β-farnesene) production. For this purpose, two resins (XAD-2 and HP-20) and three desorption solutions (water, 50/50 ethanol/water, and ethanol) were tested. The most efficient resin revealed to be the HP-20, using ethanol as desorption solution, reaching an overall total phenolic compound recovery of ca. 80% when 6 BV (bed volume) of both feed and ethanol were applied. The optimization of the resin’s process cycle pointed to 15 BV feed to be treated per cycle and using the same volume of ethanol in the desorption step, with no need for an extra resin regeneration step, stably yielding 48% total phenolic compound recovery from the spent broth for at least 4 cycles, translating into 60 BV of feed being treated per BV of resin, and with the resin being still perfectly active. The extract was characterized using LC−ESI−UHR−QqTOF−MS, and a total of 82 and 15 compounds were identified, in negative and positive ionization modes, respectively. Organic acids were the main class of compounds identified in the phenolic-rich extract, followed by phenolic compounds, saccharides, peptides or amino acids and vitamins. Additionally, the extract revealed a significant antioxidant capacity (914.1 ± 51.6 and 2764.5 ± 142.8 µmol Trolox equivalents/g-dw, respectively, with ABTS and ORAC methodologies), which might be interesting for a wide variety of applications. Full article
(This article belongs to the Special Issue Value-Added Utilization Processes of Industrial Wastes)
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10 pages, 1738 KiB  
Article
Preparation and Characterization of Porous Carbon Composites from Oil-Containing Sludge by a Pyrolysis-Activation Process
by Wen-Tien Tsai and Yu-Quan Lin
Processes 2022, 10(5), 834; https://doi.org/10.3390/pr10050834 - 23 Apr 2022
Cited by 3 | Viewed by 1450
Abstract
Large amounts of oil-containing sludge (OS) are produced in the energy, industry and services sectors. It is mainly composed of residual oil and particulate matter, thus posing an environmental threat and leading to resource depletion if it is improperly handled. In this work, [...] Read more.
Large amounts of oil-containing sludge (OS) are produced in the energy, industry and services sectors. It is mainly composed of residual oil and particulate matter, thus posing an environmental threat and leading to resource depletion if it is improperly handled. In this work, the OS feedstock was thermally treated to produce porously magnetic carbon composites (CC) using a pyrolysis-activation process. Using the data on the thermogravimetric analysis (TGA) of the OS feedstock, the thermal activation experiments were performed at 850 °C as a function of residence time (30, 60 and 90 min). The results of pore analysis for the resulting CC products showed that the Brunauer–Emmett–Teller (BET) surface area greatly decreased from 21.59 to 0.56 m2/g with increasing residence time from 30 to 90 min. This decline could be associated with continuous gasification by CO2, thus causing the removal of limited carbon on the surface of CC for a longer reaction time. Furthermore, the physical properties of the resulting CC products can be enhanced by post acid-washing due to the development of new pores from the leaching-out of inorganic minerals. The BET surface area increased from 21.59 to 40.53 m2/g at the residence time of 30 min. Obviously, the resulting CC products were porous materials with mesopores and macropores that were concurrently formed from the thermal activation treatment. These porous features were also observed by scanning electron microscopy (SEM). Full article
(This article belongs to the Special Issue Value-Added Utilization Processes of Industrial Wastes)
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19 pages, 2496 KiB  
Article
Olive Mill by-Products Thermochemical Conversion via Hydrothermal Carbonization and Slow Pyrolysis: Detailed Comparison between the Generated Hydrochars and Biochars Characteristics
by Ahmed Amine Azzaz, Camélia Matei Ghimbeu, Salah Jellai, Leila El-Bassi and Mejdi Jeguirim
Processes 2022, 10(2), 231; https://doi.org/10.3390/pr10020231 - 25 Jan 2022
Cited by 14 | Viewed by 2980
Abstract
In this research work, an ecofriendly approach was adopted for the treatment of two abundant liquid and solid agricultural wastes generated by olive mill industry: olive mill wastewater (OMWW) and raw olive pomace (ROP). It consists, firstly of the impregnation of ROP by [...] Read more.
In this research work, an ecofriendly approach was adopted for the treatment of two abundant liquid and solid agricultural wastes generated by olive mill industry: olive mill wastewater (OMWW) and raw olive pomace (ROP). It consists, firstly of the impregnation of ROP by OMWW and the conversion of the resulting impregnated sample (IROP) into hydrochars and biochars through hydrothermal carbonization (HTC) and slow pyrolysis methods, respectively. The impact of the treatment temperature on the physico-chemical properties of the derived chars was assessed by various analytical techniques. The hydrochars production yields were found to be higher than the biochars ones and associated to the lower temperature used. However, the generated biochars possess higher carbon percentage and lower volatile matter contents. In addition, the increase of the hydrothermal and pyrolysis carbonization temperatures shows an increase of macro-elements contents and a significant decrease of the O/C ratios which led to an enhancement of the high heating value for both hydrochars and biochars. The FTIR and Boehm titration analysis highlighted a significant alteration of the biochars surface chemistry compared to hydrochars evidenced by the lower amount of functional groups. The collected data emphasize on the efficient potential application of hydrochars and biochars for agricultural and environmental applications, respectively. Furthermore, it was noted that both chars have high energetic potentials and could be used for co-firing with coal in industrial boilers. Full article
(This article belongs to the Special Issue Value-Added Utilization Processes of Industrial Wastes)
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11 pages, 1012 KiB  
Article
Biocatalytic Conversion of Short-Chain Fatty Acids to Corresponding Alcohols in Escherichia coli
by Li-Jen Lin, Mukesh Saini, Chung-Jen Chiang and Yun-Peng Chao
Processes 2021, 9(6), 973; https://doi.org/10.3390/pr9060973 - 31 May 2021
Cited by 1 | Viewed by 1997
Abstract
Advanced biofuels possess superior characteristics to serve for gasoline substitutes. In this study, a whole cell biocatalysis system was employed for production of short-chain alcohols from corresponding fatty acids. To do so, Escherichia coli strain was equipped with a biocatalytic pathway consisting of [...] Read more.
Advanced biofuels possess superior characteristics to serve for gasoline substitutes. In this study, a whole cell biocatalysis system was employed for production of short-chain alcohols from corresponding fatty acids. To do so, Escherichia coli strain was equipped with a biocatalytic pathway consisting of endogenous atoDA and Clostridium acetobutylicum adhE2. The strain was further reprogrammed to improve its biocatalytic activity by direction the glycolytic flux to acetyl-CoA and recycling acetate. The production of 1-propanol and n-pentanol were exemplified with the engineered strain. By substrate (glucose and propionate) feeding, the strain enabled production of 5.4 g/L 1-propanol with productivity reaching 0.15 g/L/h. In addition, the strain with a heavy inoculum was implemented for the n-pentanol production from n-pentanoic acid. The production titer and productivity finally attained 4.3 g/L and 0.86 g/L/h, respectively. Overall, the result indicates that this developed system is useful and effective for biocatalytic production of short-chain alcohols. Full article
(This article belongs to the Special Issue Value-Added Utilization Processes of Industrial Wastes)
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Review

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20 pages, 1338 KiB  
Review
Diving into Fish Valorisation: Review Opportunities and Analyzing Azorean Fish Data
by Nádia Valério, Margarida Soares, Cândida Vilarinho, Manuela Correia and Joana Carvalho
Processes 2023, 11(7), 1998; https://doi.org/10.3390/pr11071998 - 03 Jul 2023
Cited by 2 | Viewed by 1646
Abstract
In response to the exponential growth in world population, there has been a striking surge in the volume of discarded fish worldwide. This surge is particularly evident in the fish processing industry, where a substantial amount of waste is generated, posing significant environmental [...] Read more.
In response to the exponential growth in world population, there has been a striking surge in the volume of discarded fish worldwide. This surge is particularly evident in the fish processing industry, where a substantial amount of waste is generated, posing significant environmental concerns. Consequently, the repurposing and utilisation of these waste materials have emerged as pivotal processes for the preservation of marine resources. By employing innovative strategies, valuable products can be extracted from these fish by-products, offering not only economic advantages but also contributing to mitigating environmental impacts. This comprehensive literature review focuses on exploring diverse avenues for using fish waste and extracting high-value materials such as bioactive peptides, collagen, and enzymes, elucidating their potential applications across various industries. The literature review also demonstrates the possibility of extracting various bio-compounds from highly diverse fish waste. It has been observed that there is a need for optimisation of extraction protocols, as the variation in extraction methods and respective conditions significantly affects the extraction yields of the products. Moreover, considering our specific interest in the fish species endemic to The Azores, a meticulous characterisation will be conducted, as there is limited knowledge about waste utilisation processes specific to this archipelago. Full article
(This article belongs to the Special Issue Value-Added Utilization Processes of Industrial Wastes)
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