Chemical Recovery Research Articles

Design of a synergistic combined electrodialysis/anodic oxidation system for simultaneous AMX membrane fouling mitigation and enhanced dye degradation

Electrodialysis is a common process which is widely applied for water purification and desalination or/and chemical species recovery. Solving the fouling of ion-exchange membranes is the bottleneck of this technology for stable processing along with low maintenance at large scale. This work aims to design combined electrodialysis/anodic oxidation (ED–AO) using as-prepared Pb/PbO2 anode to boost the oxidation of organic dye (methyl orange, MO) and overcome the issue of AMX membrane fouling. Hybrid ED–AO process works synergistically to accumulate, by ion-exchange reaction, MO species in the anodic Pb/PbO2 oxidative compartment to be oxidized and mineralized. As compared to single ED, excellent oxidation rates and membrane anti-fouling activities were found in ED–AO process. The characterization of the AMX membrane in single ED shows that the fouling was the main issue behind the low oxidation rate, causing a significant increase in the cell's electrical resistance, unlike in hybrid ED–AO process. Most of operating parameters including applied current density, initial concentration of MO, pH, supporting electrolyte (Na2SO4) concentration were investigated. The mechanistic pathways of MO oxidation and anti-fouling activity were discussed in depth. Through ten recycling tests, hybrid ED–AO process showed excellent stability and performance.

LETRAMENTO LITERÁRIO E SEUS BENEFÍCIOS NO AUXÍLIO À RECUPERAÇÃO DA DEPENDÊNCIA QUÍMICA

The present study deals about literary literacy and how reading might be useful in the search for recovering and socializing, contributing for the training of readers in an environment of chemical addicts recovery. It is based on bibliographical survey, and action research with qualitative approach. It aims at discussing about the importance of reading, at stimulating literary literacy, in a pleasant and diverse environment, in order to promote reading training, thus challenging patients to the process of building new knowledge. To do so, the analysis of the data was made based on the contributions and activities carried out by the research participants. In this way, the anthropology immersed in the research exerts a diversified method and insertion in the community in question. This information led to the conclusion that literary literacy plays an important role on the trajectory of patient replacement in life in society, even though it is a slow process, the research brought up good results.

Optimization of process parameters for bio-crude and value-added chemical recovery through hydrothermal liquefaction of microalgae

Optimization of process parameters for bio-crude and value-added chemical recovery through hydrothermal liquefaction of microalgae

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Investigation of the effects of different zwitterions in fabricating smart PVDF/graphene pervaporation membranes

Although membrane separation processes including pervaporation have demonstrated their as an efficiency in chemical waste treatment and resource recovery, the increasingly complex wastes generated by different industrial sectors make it almost impossible for a single membrane that has a fixed set of properties to handler these kinds of contaminants. For this reason, stimuli responsive membranes that have tunable and switchable properties are necessary to be developed. In this research, we explore the impacts of zwitterion compounds as additives to previously formulated PVDF-graphene membrane where graphene was used to facilitate β-phase induction of PVDF, enhancing its piezoelectric properties. The incorporation of zwitterions intended to even promote the β -crystal phase of PVDF, which is also facilitated by an optimized quantity of graphene. The quantified β phase of pristine PVDF- (68.7 %) was observed to increase to 79.4 %-86.32 %, when different zwitterions are added. Moreover, output voltages from piezoelectric testing of membranes under various weights generated a voltage signal up to 1.69 V for the membrane with the 3-(1-Pyridinio-1-propanesulfonate) zwitterion, named as PGzc membrane. Upon employing these membranes to dehydrate isopropanol by pervaporation, it was found out that PG shows a permeation flux (Pf) of 95.49 ± 9.18 g/m2h and 77 % water concentration in permeate (Wcp) while the PGzc.membrane displayed a Pf and Wcp of 988.84 ± 51 g/m2h and 30 %, respectively. But upon application of an external voltage, it was found out that PGzc's Wcp rises from 30 % to 83 % with increasing voltage and while the Pf gradually falls from 988.84 ± 51 g/m2h to 432.51 ± 19 g/m2h. These findings indicate that the addition of an appropriate zwitterion could significantly influence the piezoelectric properties of PVDF-graphene membranes, enhancing their tuning capability under electrical stimulation. This development is important for separation processes and technologies aimed at creating a sustainable society.

Electrochemical ammonia recovery and co-production of chemicals from manure wastewater

Electrochemical ammonia recovery and co-production of chemicals from manure wastewater

Nanofiltration and selective crystallisation as technologies for the recovery of chemicals from seawater desalination brine to be used as ingredients for Bio-based fertilisers

The majority of companies that operate desalination units produce significant quantities of brine, a hypersaline product whose disposal in the sea contributes to the degradation of local fauna and flora. The proposed process for the valorisation of seawater brine and recovery of high purity water consists of two precipitation steps for the recovery of Mg(OH)2 and CaCO3. After pH conditioning, the brine (without Mg2+ and Ca2+) is led to Nanofiltration unit for Na2SO4 separation from the NaCl - KCl rich stream. Monovalent salt stream is further concentrated by Multiple Effect Distillation evaporator and crystallizer and KCl is separated from NaCl by flotation using Sodium Dodecyl Sulfate as floating agent. The aforementioned micronutrients have readily been tested for their part in enhancing the agronomic performance of fertilising products, so they possess market potential to support local/national/European fertilisation purposes. Last but not least, such a nutrient recovery approach can ensure capital recovery within the expected time limitations of an investment and in some cases offset completely the treatment cost.

Efficient laboratory perovskite solar cell recycling with a one-step chemical treatment and recovery of ITO-coated glass substrates

The proliferation of organic–inorganic perovskite solar cells (PSCs) has garnered considerable attention due to their potential for low-cost, large-scale photovoltaic panel production. However, the inclusion of lead in PSCs poses significant sustainability challenges, necessitating effective end-of-life treatment strategies to mitigate environmental pollution and comply with electronic waste disposal regulations. In this study, we present a novel recycling system for decomposing and reclaiming the constituent materials of a typical PSC. Utilizing a one-step solution process extraction approach, we successfully preserved the chemical composition of each layer, enabling their potential reuse. This recycling method not only addresses the separation of the toxic lead component but also emphasizes the recovery of other valuable PSC layers. Notably, the commonly used hole transport layer in perovskite solar cells is Spiro-OMeTAD, which was successfully extracted with chlorobenzene, with its purity subsequently confirmed. Moreover, the removal of individual layers facilitated the retrieval of indium-doped tin oxide (ITO) conductive glass, a critical substrate in PSC fabrication. Comparative analysis of the physical and electrical properties of recycled and reference ITO substrates revealed minimal discrepancies, indicating the feasibility of reusing recycled substrates without compromising device performance. The proposed recycling technique offers a practical approach to mitigate pollution risks, minimize waste generation during the recycling process of perovskite-based solar cells, and reduce end-of-life recycling costs.

Reuse of sodium–doped iridium oxide nanoparticles as a bio–stimulating electrode by a chemical and electrochemical recovery process

A sequential chlorination and electrochemical reduction process is demonstrated to convert Na–doped iridium oxide nanoparticles into useful IrIIICl63−(aq) serving as the precursor for the fabrication of bio–stimulating electrode. The Na–doped iridium oxide nanoparticles are treated in 35 wt% hydrochloric acid at 70 °C for 18 h to form IrIVCl62−(aq) with pH of 0.3, so the latter could be readily reduced to IrIIICl63−(aq) at a potentiostatic mode of 0.6 V (vs. SCE). The oxidation state and the nature of complexing ligands for the regenerated IrIIICl63− and IrIVCl62−, as well as commercially available IrIIICl63− are validated by X–ray Absorption Spectroscopy. UV–Vis profiles of regenerated IrIVCl62−(aq) are recorded and the absorbance at 487 nm signal is benchmarked against that of standard IrIVCl62−(aq) to obtain the effective regeneration ratio of 68.6%. X–ray diffraction patterns of Na–doped iridium oxide nanoparticles before and after the annealing treatment indicate the amorphous structure facilitates the chlorination step. The regenerated IrIIICl63− is reused to synthesize Na–doped iridium oxide thin film serving as a bio–stimulating electrode for implantable bio–electronics. The regenerated Na–doped iridium oxide thin film reveals a charge-storage capacity of 0.32 mC/cm2-nm and impressive stability that are comparable to those of fresh Na–doped iridium oxide thin film derived from commercially available IrIIICl63−.

A Review of Bio-Based Activated Carbon Properties Produced from Different Activating Chemicals during Chemicals Activation Process on Biomass and Its Potential for Malaysia

Activated carbon is the preferred adsorbent for gas and water treatment in various industry across the world due to its efficiency, reliability, and accessibility. Recently, in Malaysia, studies are mainly focused on the fabrication of activated carbon from lignocellulosic biomass-based precursors from agricultural waste such as coconut shell, rice husk, and palm kernel shell. Activated carbon fabrication is a two-step process; the precursor will first undergo carbonization, then, activation is carried out either physically or chemically to develop its porous surface for adsorption purposes. The main benefit of activated carbon is the customizable pore structure for different utilization, which can be easily achieved by the chemical activation process. The types and concentration of chemicals used for activation, pre-treatment of precursor, duration of the activation process, and the mass ratio of precursor to chemicals are proven to effectively influence the resulting pore structure. However, the chemicals used in the activation process can be harmful to the environment. Thus, the chemical recovery process is necessary after the activation process. Nonetheless, more in-depth research on producing activated carbon from abundant biomass materials with bio-based chemical agents for activation is needed to achieve an ecological and sustainable manufacturing process.

Recovery of 400 Chemicals with Three Extraction Methods for Low Volumes of Human Plasma Quantified by Instrumental Analysis and In Vitro Bioassays.

Human biomonitoring studies are important for understanding adverse health outcomes caused by exposure to chemicals. Complex mixtures of chemicals detected in blood - the blood exposome - may serve as proxies for systemic exposure. Ideally, several analytical methods are combined with in vitro bioassays to capture chemical mixtures as diverse as possible. How many and which (bio)analyses can be performed is limited by the sample volume and compatibility of extraction and (bio)analytical methods. We compared the extraction efficacy of three extraction methods using pooled human plasma spiked with >400 organic chemicals. Passive equilibrium sampling (PES) with polydimethylsiloxane (PDMS) followed by solid phase extraction (PES + SPE), SPE alone (SPE), and solvent precipitation (SolvPrec) were compared for chemical recovery in LC-HRMS and GC-HRMS as well as effect recovery in four mammalian cell lines (AhR-CALUX, SH-SY5Y, AREc32, PPARγ-BLA). The mean chemical recoveries were 38% for PES + SPE, 27% for SPE, and 61% for SolvPrec. PES + SPE enhanced the mean chemical recovery compared to SPE, especially for neutral hydrophobic chemicals. PES + SPE and SolvPrec had effect recoveries of 100-200% in all four cell lines, outperforming SPE, which had 30-100% effect recovery. Although SolvPrec has the best chemical recoveries, it does not remove matrix like inorganics or lipids, which might pose problems for some (bio)analytical methods. PES + SPE is the most promising method for sample preparation in human biomonitoring as it combines good recoveries with cleanup, enrichment, and potential for high throughput.

Platform chemicals recovery from spent coffee grounds aqueous-phase pyrolysis oil

Spent coffee grounds (SCG) are a valuable biogenic waste diffused on a global scale, containing a significant amount of extractives. The aim of this study is to characterize the pyrolysis oil fractions, under various process conditions, targeting their potential applications as biofuels and source of valuable chemicals. Pyrolysis tests were carried out in the range of 400–550 °C with a laboratory-scale screw reactor and a two-step solvent extraction process, was conducted for the aqueous bio-oil phase. The results showed that heavy organic bio-oil resulted in a carbon rich biofuel, with a carbon content of up to 63 % (w/w) and HHV up to 34.8 MJ/kg. Chloroform was selective in extracting xantines (68–74 % of the peak area), furans, phenols, and fatty acids from the aqueous phase, while the ethyl acetate extract was abundant in p-benzoquinone (70–83 % of the peak area), a key-player chemical for the petrochemical industry. The residual unextracted water phase is very rich in organic acids i.e. acetic, propionic, and formic-whose concentration is in the range 47 g/L and 87.9 g/L. The results of this study outline how solvent extraction is a promising technique for extracting valuable chemicals to improve the economic potential of spent coffee grounds pyrolysis-based biorefinery.

Molecularly engineered cardanol derived epoxy vitrimers based on dynamic disulfide and dynamic ester exchanges with desirable dynamic response, degradability, and recyclability

Dynamic covalent chemistry provides a solution to the recycling problem of epoxy resins, and the graphene functional composites. Nevertheless, the study on chemical structures of the curing agent, and the type of dynamic covalent bonds associated with the nature of the epoxy resins still face challenge due to unclear mechanism and improper design strategy. Herein, a bio-based epoxy monomer was designed from cardanol, and used to fabricate a double dynamically crosslinked epoxy vitrimer. The mechanical properties, dynamic mechanical properties, thermal stability, relaxation behavior, self-healing efficiency, recovery, and reprocessing efficiency of the resulting resins were investigated, focusing on the effects of the soft and hard structure of the curing agent, and the types of dynamic covalent bonds. Bio-based epoxy vitrimers demonstrated several advantages, including multi-stimulus responsiveness, multi-channel self-healing ability, mechanical and chemical recovery, and biodegradability. Specifically, the epoxy vitrimers containing rigid furan rings exhibited better mechanical properties (6.85 MPa) and stability (Tg = 40.81 °C) compared to those with flexible fatty chains. Additionally, the double dynamically crosslinked vitrimer showed faster stress relaxation time (5.6 min) and lower activation energy (36.58 kJ/mol) compared to systems with a single dynamic bond. Finally, the addition of graphene enabled the production of cardanol-based composites with conductivity. Overall, the ease with bio-based epoxy vitrimer and its composites with excellent degradability can be fabricated, utilized, recycled and re-used, which is a novel direction for sustainable composites.

A sensitive method to determine 210Po and 210Pb in environmental samples by alpha spectrometry using CuS micro-precipitation

A new sensitive method to determine polonium-210 (210Po) and lead-210 (210Pb) in a diversity of environmental samples was developed. For fresh and marine waters, Po was pre-concentrated using a titanium (III) hydroxide (Ti(OH)3) co-precipitation. Solid environmental samples were digested with nitric acid (HNO3) and hydrogen peroxide (H2O2). The alpha thin layer source was prepared using CuS micro-precipitation and 210Po was measured by alpha spectrometry. Lead-210 was left to decay for up to a year and indirectly measured via its progeny, 210Po. The chemical recoveries for 210Po and 210Pb were high, 90% and 97%, respectively, for a large variety of samples and a very low minimum detectable activity (MDA) was obtained. The method was validated using standardized solutions and certified reference materials.

High-value recycling and biodegradation of polyolefin materials

The pollution of plastic materials has seriously affected global environmental problems. Polyolefin materials are widely used as raw materials for plastics. This is due to their practical physical properties and low cost. However, there are major challenges in the disposal of waste polyolefin materials. Recycling and degradation have emerged as the two main approaches for the treatment of plastic waste today. Through a comprehensive literature analysis and review of methods, this paper provides an in-depth study of recycling and biodegradation of polyolefin materials. The study is based on a detailed search of several papers through Google Scholar in order to provide valuable insights into the different methods that are used for the recycling and biodegradation of polyolefins. The review summarizes the most effective technologies for recycling and biodegradation, while highlighting recent advances and future directions in the field. In particular, the research has focused on two main approaches: closed-loop recycling and chemical recovery. The latter technology is aimed at non-polluting biodegradation, which has become an increasingly important topic of interest for the scientific community. Given the urgency of the environmental challenges posed by polyolefins, the development of efficient and sustainable recycling and degradation methods is essential to create a circular economy and ensure a sustainable future.

Agricultural Plastic Waste Management

This article aims at describing both the studies and results implemented in the framework of the H2020-EU research project “RECOVER: New bio-recycling routes for food packaging and agricultural plastic waste” which deals with the sustainability of innovative biodegradation processes for plastic waste and production, in any environmental, social, economic and safety matters. In such a framework, the POLOG University Centre (Livorno, Italy), reconstructed and analyzed the actual farm plastic waste supply chain, as described in the following sections. The first section is introductive and it has been intended as a primer to the most common different types of plastic materials. The second section has deserved to be a state of the art on the most relevant issues raised in plastic waste management. The third section deals with suitable approaches to address the environmental side effects of rapidly growing plastics production, use, and disposal. Some of these approaches were listed, such as physical treatment of the polymeric components, plastic reduction use and employment as much as mechanical and/or chemical recycling and energy recovery. The fourth section shows how some of the above main issues, which raise coping with plastic reduction and recycling, are suited to be coped with from a logistics perspective. Such logistics belong to the basic needs due to tackling any plastic waste supply chain, i.e. collection and transport to intermediate stock and final delivery to recycling plants and/or brownfields, applying the set of methodologies and techniques drawn from the well-known field of pick-up-anddelivery models. These last tasks become crucial when the main effort has addressed the enforcement of any feasible changes from the use of items made in old high environmental intrusive to their replacement with new agricultural and biodegradable plastics. The paper goes to end presenting shortly of a few suitable solutions that could be proposed and applied to the entire plastic waste supply chain. Finally, some concrete aspects of each phase of the supply chain were discussed and it was highlighted how much each of these can be best used in addressing the problem known throughout the world as the problem of the emergency of old plastic waste.

Hydrogen production and value-added chemical recovery from the photo-reforming process using waste plastics

Photo-reforming is a novel and promising green H2 production method with enhanced catalytic efficiency via optimizing the oxidation reaction by introducing an organic compound as the sacrificial agent. This study focuses on the degradation of different plastic wastes, such as polyethylene terephthalate (PET), low-density polyethylene (LDPE), and polystyrene (PS) as sacrificial agents in the photo-reforming process for H2 production. The process was optimized by evaluating H2 production under different plastic pretreatment methods and the polymer-to-catalyst ratio. Disodium terephthalate (Na2TP) and terephthalic acid (TPA) were identified as byproducts after the alkaline pretreatment of PET, and these extracted products were re-applied in the photo-reforming process and tested for their applicability in H2 generation. The degradation of plastics and their respective pretreatment byproducts were characterized using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and thermogravimetric analysis (TGA). PET was the best sacrificial agent in H2 production under almost all conditions whereas 4026 μmol/gcat/gPET was produced under ethanol-induced pretreatment at 40 °C. This combined analysis indicates H2 can be successfully generated from LDPE, PET, PS, and degradation byproducts. Further, TPA and Na2TP can be extracted from the reaction mixture for reuse. This study revealed the mechanisms of using plastics as sacrificial agents and the intermediate byproducts in the photo-reforming process on H2 evolution efficiency. It provides the opportunity for green H2 generation while degrading plastic waste by solving multiple environmental issues with revenue generation.

Enhanced chemical recovery of phosphorus from residues of recirculating aquaculture systems (RAS)

In recirculating aquaculture systems, cultivated fish cannot incorporate all the phosphate contained in the feed. Excess phosphate ends up in the culture water and in the sludge produced. If the sludge cannot be valorised directly in agriculture, a chemical recovery as concentrated phosphate is an interesting option to help closing the phosphorus cycle. This study investigates the extent to which accumulated phosphorus can be recovered by acid re-dissolution with subsequent precipitation on sludge from two different recirculating aquaculture systems cultivating African Catfish (Clarias gariepinus). Acid treatment could increase the ratio of dissolved phosphorus available for subsequent precipitation by 53% for extensive and by 61% for intensive fish farming. With the consecutive precipitation in total up to 86% of the phosphorus from the sludge could be recovered. Phosphorus re-dissolution with citric acid requires the highest amount of acid per g dry matter as well as of sodium hydroxide for subsequent precipitation. Sulfuric and nitric acids have comparably lower demands.

Removal and Reuse of Collagen, Gelatine and Total Chromium from a Raw Leather Industry Wastewater using a Sequential Up flow Anaerobic Sludge Blanket Digestion (UASB) / Aerobic Forward Osmosis (FO) Reactor Configuration

Collagen, gelatine and total chromium recovery was achieved from the sequential upflow anaerobic sludge blanket digestion (UASB) reactor sludge and concentrate of forward osmosis (FO) treating raw leather industry wastewater. It is aimed to reduce the cost of raw materials in leather industry process by reusing the collagen, gelatine and total chromium from the leather industry process during tanning. The recoveries of collagen and gelatine, total chromium was 78%, 80% and 27% respectively from the waste sludge in UASB process while the recoveries of these chemicals were 95%, 96% and 99% in the concentrate of FO. The maximum 85% CODtotal, 94% CODdissolved, 89% total-N, 88% total-P, 87% color, 87% total chrome (Cr+3 + Cr+6), 86% TOC, 87% SO3-2, 90% percentage of exchangeable sodium, 87% sodium adsorption rate (SAR), 84% sodium carbonate residue (RSC), 92% Cl-1, 92% SO4-2, 93% total salt, 88% B+3, 94% NO3-, 94% NH4+, 99% fecal coliform, 94% TSS, 93% EC25x106 removal efficiencies were measured to output anaerobic UABS reactor in leather industry wastewater. The maximum 99% CODtotal, 99% CODdissolved, 99% total-N, 99% total-P, 99% color, 99% total chrome (Cr+3 + Cr+6), 99% TOC, 99% SO3-2, 99% percentage of exchangeable sodium, 99% sodium adsorption rate (SAR), 99% sodium carbonate residue (RSC), 99% Cl-1, 99% SO4-2, 99% total salt, 99% B+3, 99% NO3-, 99% NH4+, 99% fecal coliform, 99% TSS, 99% EC25x106 removal efficiencies were observed to output aerobic FO reactor in leather industry wastewater. The costs of anaerobic UASB and aerobic FO processes are 0.57 euro and 0.145 euro, respectively, to treat 1 m3 leather industry wastewater. The cost of the consecutive total system is 0.715 euro for the treatment of 1m3 leather industry wastewater. The methane gas obtained in the UABS reactor is electrical energy and the electrical energy income was calculated as 1.9 euro from 1 m3 anaerobic waste sludge. The income to be obtained from the recovery of total chromium, collagen and gelatine from UABS and FO process is 2.75 Euro/l. As a result, the total cost decreases from 1.55 Euro/l to 0.715 Euro/l after aerobic FO process. The cost of these consecutive treatment processes is reduced by the production of methane gas and is increased the recovery of economic chemicals.

Current technological options for recycling packaging waste: Challenges and opportunities in India

AbstractPackaging in India comprises around 59% of total plastic consumption, with most of the waste originating from single‐use and short shelf‐life products. The plastic recycling industry is primarily made up of informal processing units which have predominantly been recycling Polyethylene terephthalate (PET) waste due to ease of availability, sorting, and higher upscale values than most other single‐use packaging. Other packaging, such as Polyethylene (PE) shopping bags, thin film and multi‐material packaging waste is either directed to downcycling, incineration or landfill. About 94% of total recycling in India is carried out through mechanical recycling, which comes through informal and fragmented recycling units. Most of the recycling units in India rely on rudimentary technologies. One example is a visual sorting system that involves manual handling to recycle plastic waste, which is resource and time intensive. There has been some advancement towards chemical and energy recovery techniques, but mostly been limited to pilot‐scale deployment. This article explores the existing and emerging technological options suitable for recycling post‐consumer flexible plastic packaging waste in India. It also discusses the status of multi‐material packaging waste, and the advancement being made for its recycling. The paper also explores India's increased momentum in the use of innovative recycling techniques, such as distributed recycling and manufacturing techniques and plastic waste in steel manufacturing.This article is categorized under: Climate and Environment > Ecosystem Services Climate and Environment > Circular Economy Emerging Technologies > Materials