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Innovative Applications of Wastes, Low-Cost and Recycled Materials

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A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Green Materials".

Deadline for manuscript submissions: closed (10 May 2023) | Viewed by 21512

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Special Issue Editor

Prof. Dr. Igor Cretescu

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Guest Editor

“Cristofor Simionescu“ Faculty of Chemical Engineering and Environmental Protection, Gheorghe Asachi” Technical University of Iasi, Iasi, Romania
Interests: Circular Economy; recovery and recycling of valuable components from wastes; remediation of environmental components (water, air and soil); low-cost materials (sorbents, catalysts, insulators, building bricks, cements, etc.)

Special Issue Information

Dear Colleagues,

In recent decades, the increases in population and human development, as well as agro-industrial activities, have induced increasing amounts of waste. This contamination generates consequent human health problems and harms different compartments of the environment. Recycled materials are emerging as a new area of research to reduce environmental issues. Indeed, low-cost materials are used more and more intensively in many fields, especially where the traditional materials are expensive and could be successfully replaced by low-cost materials, which are generally recovered from different kinds of wastes or are based on low-cost raw materials and need only an innovative treatment at low energy costs.

“Innovative Applications of Wastes, Low-Cost and Recycled Materials” is a Special Issue devoted to an aspect of environmental protection aiming to reduce pollution by using low-cost recyclable materials. This new generation of materials could be used in many domains, such as construction, water/wastewater treatment, the development of innovative ecological devices and equipment, etc.

Using this category of materials instead of traditional materials is a new avenue for inventing surprising applications with high efficiency and performance.

Accordingly, the editorial committee welcomes research and review articles as well as proceedings from conferences relevant to the topics of this journal.

Prof. Dr. Igor Cretescu
Guest Editor

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Keywords

recovery and recycling of valuable components from wastes
remediation of environmental components (water, air and soil) in the context of Circular Economy
development and production of low-cost materials (sorbents, catalysts, insulators, bricks, cements, glasses, panels (decorative facades and walls for buildings), etc.)
recycled materials

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Published Papers (6 papers)

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Research

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23 pages, 2889 KiB

Open AccessArticle

Removal of Methylene Blue from Aqueous Solution by Mixture of Reused Silica Gel Desiccant and Natural Sand or Eggshell Waste

by Tatjana Juzsakova, Ali Dawood Salman, Thamer Adnan Abdullah, Rashed Taleb Rasheed, Balázs Zsirka, Rasha R. Al-Shaikhly, Brindusa Sluser and Igor Cretescu

Materials 2023, 16(4), 1618; https://doi.org/10.3390/ma16041618 - 15 Feb 2023

Cited by 10 | Viewed by 2701

Abstract

The purpose of this work was to develop, characterize and test new low-cost materials suitable for removing methylene blue dye from water and wastewater by adsorption. The solid materials consisted of silica gel powder (SG), silica gel mixed with eggshell powder (SG-ES) and a mixture of silica gel with sand from the western Iraqi desert (SG-SI). The samples were milled by using an electrical mixer and a ball mill, followed by a drying step. In addition, desert sand was acid-treated in order to remove impurities. The structure and chemical composition of the samples were investigated by X-ray diffraction (XRD), a scanning electron microscopy technique equipped with an energy-dispersive X-ray spectrometer (SEM-EDX), a low-temperature nitrogen adsorption (BET) technique, thermo-analytical (TG/TGA) measurements and Fourier-transformed infrared spectroscopy (FTIR). The previously mentioned materials were tested to remove methylene blue from an aqueous solution. The adsorption experiments were monitored by ultraviolet–visible (UV-Vis) spectrophotometry and showed that SG and SG-ES gave promising results for the methylene blue removal from water. After 40 min of treatment of the aqueous solution containing 10 mg/L of MB at room temperature, the tested SG, SG-ES and SG-SI materials were found to have 86%, 80% and 57% dye adsorption efficiency, respectively. Taking into consideration not only the adsorption activity of the studied material but their availability, cost and concepts of cleaner production and waste minimization, the developed silica gel with eggshell can be considered as a good, cost-effective alternative to commercially available activated-carbon-based adsorbents. Different kinetic and isotherm models were fitted to the experimental results. A pseudo-second-kinetics-order model revealed high correlation fitting, while the Freundlich model was found to appropriately describe the adsorption isotherm. The thermal stability during the possible regeneration process of the SG-ES adsorbent mixture and its interaction mechanism with cationic dye was discussed. Full article

(This article belongs to the Special Issue Innovative Applications of Wastes, Low-Cost and Recycled Materials)

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19 pages, 2442 KiB

Open AccessArticle

Prediction of Strength and CBR Characteristics of Chemically Stabilized Coal Gangue: ANN and Random Forest Tree Approach

by Muhammad Nasir Amin, Mudassir Iqbal, Mohammed Ashfaq, Babatunde Abiodun Salami, Kaffayatullah Khan, Muhammad Iftikhar Faraz, Anas Abdulalim Alabdullah and Fazal E. Jalal

Materials 2022, 15(12), 4330; https://doi.org/10.3390/ma15124330 - 18 Jun 2022

Cited by 16 | Viewed by 2226

Abstract

Coal mining waste in the form of coal gangue (CG) was established recently as a potential fill material in earthworks. To ascertain this potential, this study forecasts the strength and California Bearing Ratio (CBR) characteristics of chemically stabilized CG by deploying two widely used artificial intelligence approaches, i.e., artificial neural network (ANN) and random forest (RF) regression. In this research work, varied dosage levels of lime (2, 4, and 6%) and gypsum (0.5, 1, and 1.5%) were employed for determining the unconfined compression strength (UCS) and CBR of stabilized CG mixes. An experimental study comprising 384 datasets was conducted and the resulting database was used to develop the ANN and RF regression models. Lime content, gypsum dosage, and 28 d curing period were considered as three input attributes in obtaining three outputs (i.e., UCS, unsoaked CBR, and soaked CBR). While modelling with the ANN technique, different algorithms, hidden layers, and the number of neurons were studied while selecting the optimum model. In the case of RF regression modelling, optimal grid comprising maximal depth of tree, number of trees, confidence, random splits, enabled parallel execution, and guess subset ratio were investigated, alongside the variable number of folds, to obtain the best model. The optimum models obtained using the ANN approach manifested relatively better performance in terms of correlation coefficient values, equaling 0.993, 0.995, and 0.997 for UCS, unsoaked CBR and soaked CBR, respectively. Additionally, the MAE values were observed as 45.98 kPa, 1.41%, and 1.18% for UCS, unsoaked CBR, and soaked CBR, respectively. The models were also validated using 2-stage validation processes. In the first stage of validation of the model (using unseen 30% of the data), it was revealed that reliable performance of the models was attained, whereas in the second stage (parametric analysis), results were achieved which are corroborated with those in existing literature. Full article

(This article belongs to the Special Issue Innovative Applications of Wastes, Low-Cost and Recycled Materials)

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27 pages, 10981 KiB

Open AccessArticle

Valorization of β-Chitin Extraction Byproduct from Cuttlefish Bone and Its Application in Food Wastewater Treatment

by Nisrine Nouj, Naima Hafid, Noureddine El Alem, Ingrid Ioana Buciscanu, Stelian Sergiu Maier, Petrisor Samoila, Gabriela Soreanu, Igor Cretescu and Catalina Daniela Stan

Materials 2022, 15(8), 2803; https://doi.org/10.3390/ma15082803 - 11 Apr 2022

Cited by 12 | Viewed by 3248

Abstract

The nontoxicity, worldwide availability and low production cost of cuttlefish bone products qualify them an excellent biocoagulant to treat food industry wastewater. In this study, cuttlefish bone liquid waste from the deproteinization step was used as a biocoagulant to treat food industry wastewater. This work concerns a waste that has never before been investigated. The objectives of this work were: the recovery of waste resulting from cuttlefish bone deproteinization, the replacementof chemical coagulants with natural ones to preserve the environment, and the enhancement ofthe value of fishery byproducts. A quantitative characterization of the industrial effluents of a Moroccan food processing plant was performed. The physicochemical properties of the raw cuttlefish bone powder and the deproteinization liquid extract were determined using specific analysis techniques: SEM/EDX, FTIR, XRD and ¹H-NMR. The protein content of the deproteinization liquid was determined by OPA fluorescent assay. The zeta potential of the liquid extract was also determined. The obtained analytical results showed that the deproteinization liquid waste contained an adequate amount of soluble chitin fractions that could be used in food wastewater treatment. The effects of the coagulant dose and pH on the food industrial effluents were studied to confirm the effectiveness of the deproteinization liquid extract. Under optimal conditions, the coagulant showed satisfactory results. Process optimization was performed using the Box–Behnken design and response surface methodology. Thus, the optimal removal efficiencies predicted using this model for turbidity (99.68%), BOD₅ (97.76%), and COD (82.92%) were obtained at a dosage of 8 mL biocoagulant in 0.5 L of food processing wastewater at an alkaline pH of 11. Full article

(This article belongs to the Special Issue Innovative Applications of Wastes, Low-Cost and Recycled Materials)

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15 pages, 3363 KiB

Open AccessArticle

Using Fly Ash Wastes for the Development of New Building Materials with Improved Compressive Strength

by Maria Harja, Carmen Teodosiu, Dorina Nicolina Isopescu, Osman Gencel, Doina Lutic, Gabriela Ciobanu and Igor Cretescu

Materials 2022, 15(2), 644; https://doi.org/10.3390/ma15020644 - 15 Jan 2022

Cited by 12 | Viewed by 2686

Abstract

Fly ash wastes (silica, aluminum and iron-rich materials) could be smartly valorized by their incorporation in concrete formulation, partly replacing the cement. The necessary binding properties can be accomplished by a simple procedure: an alkali activation process, involving partial hydrolysis, followed by gel formation and polycondensation. The correlations between the experimental fly ash processing conditions, particle characteristics (size and morphology) and the compressive strength values of the concrete prepared using this material were investigated by performing a parametric optimization study to deduce the optimal processing set of conditions. The alkali activation procedure included the variation of the NaOH solutions concentration (8–12 M), temperature values (25–65 °C) and the liquid/solid ratio (1–3). The activation led to important modifications of the crystallography of the samples (shown by powder XRD analysis), their morphologies (seen by SEM), particle size distribution and Blaine surface values. The values of the compressive strength of concrete prepared using fly ash derivatives were between 16.8–22.6 MPa. Thus, the processed fly ash qualifies as a proper potential building material, solving disposal-associated problems, as well as saving significant amounts of cement consumed in concrete formulation. Full article

(This article belongs to the Special Issue Innovative Applications of Wastes, Low-Cost and Recycled Materials)

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19 pages, 3812 KiB

Open AccessArticle

Novel Liquid Chitosan-Based Biocoagulant for Treatment Optimization of Fish Processing Wastewater from a Moroccan Plant

by Nisrine Nouj, Naima Hafid, Noureddine El Alem and Igor Cretescu

Materials 2021, 14(23), 7133; https://doi.org/10.3390/ma14237133 - 23 Nov 2021

Cited by 10 | Viewed by 2989

Abstract

A novel liquid chitosan-based biocoagulant for treating wastewater from a Moroccan fish processing plant was successfully prepared from shrimp shells (Parapenaeus longirostris), the most abundant fish by-products in the country. The shells were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transforms infrared spectroscopy. Using chitosan without adding acetic acid helps to minimize its negative impact on the environment. At the same time, the recovery of marine shellfish represents a promising solution for the management of solid fish waste. In order to test the treatment efficiency of the biocoagulant developed, a qualitative characterization of these effluents was carried out beforehand. The optimization process was conducted in two steps: jar-test experiments and modeling of the experimental results. The first step covered the preliminary assessment to identify the most influential operational parameters (experimental conditions), whereas the second step concerned the study of the effects of three significant operational parameters and their interactions using a Box–Behnken experimental design. The variables involved were the concentration of coagulant (X₁), the initial pH (X₂), and the temperature (X₃) of the wastewater samples, while the responses were the removal rates of turbidity (Y₁) and BOD₅ (Y₂). The regression models and response surface contour plots revealed that chitosan as a liquid biocoagulant was effective in removing turbidity (98%) and BOD₅ (53%) during the treatment. The optimal experimental conditions were found to be an alkaline media (pH = 10.5) and a biocoagulant dose of 5.5 mL in 0.5 L of fish processing wastewater maintained at 20 °C. Full article

(This article belongs to the Special Issue Innovative Applications of Wastes, Low-Cost and Recycled Materials)

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Review

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39 pages, 13868 KiB

Open AccessReview

Scandium Recovery Methods from Mining, Metallurgical Extractive Industries, and Industrial Wastes

by Ali Dawood Salman, Tatjána Juzsakova, Saja Mohsen, Thamer Adnan Abdullah, Phuoc-Cuong Le, Viktor Sebestyen, Brindusa Sluser and Igor Cretescu

Materials 2022, 15(7), 2376; https://doi.org/10.3390/ma15072376 - 23 Mar 2022

Cited by 26 | Viewed by 6283

Abstract

The recovery of scandium (Sc) from wastes and various resources using solvent extraction (SX) was discussed in detail. Moreover, the metallurgical extractive procedures for Sc recovery were presented. Acidic and neutral organophosphorus (OPCs) extractants are the most extensively used in industrial activities, considering that they provide the highest extraction efficiency of any of the valuable components. Due to the chemical and physical similarities of the rare earth metals, the separation and purification processes of Sc are difficult tasks. Sc has also been extracted from acidic solutions using carboxylic acids, amines, and acidic β-diketone, among other solvents and chemicals. For improving the extraction efficiencies, the development of mixed extractants or synergistic systems for the SX of Sc has been carried out in recent years. Different operational parameters play an important role in the extraction process, such as the type of the aqueous phase and its acidity, the aqueous (A) to organic (O) and solid (S) to liquid (L) phase ratios, as well as the type of the diluents. Sc recovery is now implemented in industrial production using a combination of hydrometallurgical and pyrometallurgical techniques, such as ore pre-treatment, leaching, SX, precipitation, and calcination. The hydrometallurgical methods (acid leaching and SX) were effective for Sc recovery. Furthermore, the OPCs bis(2-ethylhexyl) phosphoric acid (D2EHPA/P204) and tributyl phosphate (TBP) showed interesting potential taking into consideration some co-extracted metals such as Fe(III) and Ti(IV). Full article

(This article belongs to the Special Issue Innovative Applications of Wastes, Low-Cost and Recycled Materials)

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