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Urban mining of obsolete computers by manual dismantling and waste printed circuit boards by chemical leaching and toxicity assessment of its waste residues
2021
Arya, Shashi | Patel, Aneri | Kumar, Sunil | Pau-Loke, Show
Waste residues and acidic effluents (post-processing of E-waste) released into the local surroundings cause perilous environmental threats and potential risks to human health. Only limited research and information are available toward the sustainable management of waste residues generated post resource recovery of E-waste components. In the present study, the manual processing of obsolete computer (keyboard, monitor, CPU, and mouse) and chemical leaching of waste printed circuit boards (WPCBs) (motherboard, hard drive, DVD drive, and power supply) were performed for urban mining. The toxicity characteristics of typical pollutants in the residues of the WPCBs (post chemical leaching) were studied by toxicity characteristics leaching procedure (TCLP) test. Manual dismantling techniques resulted in an efficient urban mining concept with an overall average profit estimation of INR 2513.73/US$ 34.59. The chemical leaching of WPCBs showed a high concentration of metal leaching like Cu (229662 ± 575.3 mg/kg) and Pb (36785.67 ± 13.07 mg/kg) in the motherboard after stripping epoxy coating. The toxicity test revealed that the concentration of Cu (245.746 ± 0.016 mg/l) in the treated waste residue and Cu (430.746 ± 0.0015 mg/l) and Pb (182.09 ± 0.0035 mg/l) in the non-treated waste residue exceeded the threshold limit. The concentrations of other elements As, Cd, Co, Cr, Ag, Mn, Zn, Ni, Fe, Se, and In were within the permissible limit. Hence, the waste residue stands non-hazardous except Cu and Pb. Stripping out the epoxy coating of WPCBs enhances the metal leaching concentrations. The study highlighted that efficient and appropriate E-waste urban mining has immense potential in tracing the waste scrap into secondary resources. This study also emphasized that the final processed waste residue (left unattended or discarded due to lack of appropriate skill and technology) can be taken into consideration and exploited for value-added materials.
Show more [+] Less [-]Plastics, (bio)polymers and their apparent biogeochemical cycle: An infrared spectroscopy study on foraminifera
2021
Birarda, Giovanni | Buosi, Carla | Caridi, Francesca | Casu, Maria Antonietta | De Giudici, Giovanni | Di Bella, Letizia | Medas, Daniela | Meneghini, Carlo | Pierdomenico, Martina | Sabbatini, Anna | Surowka, Artur | Vaccari, Lisa
To understand the fate of plastic in oceans and the interaction with marine organisms, we investigated the incorporation of (bio)polymers and microplastics in selected benthic foraminiferal species by applying FTIR (Fourier Transform Infrared) microscopy. This experimental methodology has been applied to cultured benthic foraminifera Rosalina globularis, and to in situ foraminifera collected in a plastic remain found buried into superficial sediment in the Mediterranean seafloor, Rosalina bradyi, Textularia bocki and Cibicidoides lobatulus. In vitro foraminifera were treated with bis-(2-ethylhexyl) phthalate (DEHP) molecule to explore its internalization in the cytoplasm. Benthic foraminifera are marine microbial eukaryotes, sediment-dwelling, commonly short-lived and with reproductive cycles which play a central role in global biogeochemical cycles of inorganic and organic compounds. Despite the recent advances and investigations into the occurrence, distribution, and abundance of plastics, including microplastics, in marine environments, there remain relevant knowledge gaps, particularly on their effects on the benthic protists. No study, to our knowledge, has documented the molecular scale effect of plastics on foraminifera.Our analyses revealed three possible ways through which plastic-related molecules and plastic debris can enter a biogeochemical cycle and may affect the ecosystems: 1) foraminifera in situ can grow on plastic remains, namely C. lobatulus, R. bradyi and T. bocki, showing signals of oxidative stress and protein aggregation in comparison with R. globularis cultured in negative control; 2) DEHP can be incorporated in the cytoplasm of calcareous foraminifera, as observed in R. globularis; 3) microplastic debris, identified as epoxy resin, can be found in the cytoplasm and the agglutinated shell of T. bocki.We hypothesize that plastic waste and their associated additives may produce modifications related to the biomineralization process in foraminifera. This effect would be added to those induced by ocean acidification with negative consequences on the foraminiferal biogenic carbon (C) storage capacity.
Show more [+] Less [-]Occurrence and distribution of microplastics in beach sediments along Phuket coastline
2021
Akkajit, Pensiri | Tipmanee, Danai | Cherdsukjai, Phaothep | Suteerasak, Thongchai | Thongnonghin, Sudarat
Phuket is a popular tourism destination in Thailand. This study examined the distribution of microplastics found on beaches along the East and West coasts of Phuket including Tri Trang, Patong, Kalim, Chalong, Makham, and Rawai beaches. A total of 18 samples from a 0.5 m × 0.5 m quadrat at the intertidal zone were sorted into >300-μm and 20–300-μm size classes. For all sizes combined, the mean abundance was 188.3 ± 34.5 items kg⁻¹. White (29.2%) and fiber (85.6%) were the most abundant plastic; and the polymer types based on μFTIR analysis were PET > PS > PP > PU > PVC > Epoxy with a great amount of cotton and regenerated cellulose also detected. Principal component analysis indicated the correlation between PET, regenerated cellulose, PP and PU with Chalong and Patong beaches, suggesting that highly visited tourist beaches with harbor activities, and a tourist departure point, are possible sources of microplastics.
Show more [+] Less [-]Nanoscale Zerovalent Iron Immobilized on Functionalized Nonwoven Cotton Fabric for As(V) Adsorption
2021
Korpayev, Serdar | Kavaklı, Cengiz | Kavaklı, Pınar Akkaş
A functionalized nonwoven cotton fabric-Fe(0) (denoted as FNCF-ZVI) as a novel adsorbent material was synthesized in two main steps for water treatment of arsenate ions. Firstly, the Fe(III)-immobilized chelating fabric with iminodiacetic acid (IDA) functional groups was synthesized through an epoxy group–containing glycidyl methacrylate (GMA) grafted to the nonwoven cotton fabric (NCF) via plasma-initiated emulsion graft polymerization. Subsequently, the obtained Fe(III)-immobilized FCNF was followed by a reduction of Fe(III) into Fe(0) to obtain stabilized nanoscale zerovalent iron (ZVI) on the surface of FNCF. FNCF-ZVI was applied for arsenic(V) removal in batch experiments at different pH values (2.00–9.00) and concentrations ranging between 1 and 500 mg/L As(V). The FNCF-ZVI had a positive impact on the absorption of As(V) species under acidic conditions, and the highest adsorption was seen at a pH value of 3.00. The adsorption equilibrium of adsorbent was reached in 420 min with initial solution concentrations at 1 mg/L, 10 mg/L, and 50 mg/L, and the process better fitted to the nonlinear pseudo-second-order model than to the nonlinear pseudo-first-order model. The resulting FNCF-ZVI showed a high maximum adsorption capacity of 158.73 mg/g at 35 °C for As(V) adsorption, and the adsorption data fitted the Freundlich isotherm model. Regeneration studies displayed that after 3 times usage, the adsorption capacity can remain up to 86%. It has been observed that ZVI nanoparticles have superior adsorption capacity compared to Fe(III) under their optimum conditions.
Show more [+] Less [-]Study on polymeric coatings on fly ash concrete under seawater
2021
Boopaphi, Roselin Sobha Joseph | Dasnamoorthy, Ramachandran | Chandrasekaran, Manoj Kumaar | Vishwakarma, Vinita
This study is focused on polymeric coatings on fly ash concrete submerged under seawater. The specimens were casted and coated with acrylic resin and epoxy resin of three layers each. The mechanical, durability, and microstructural properties of coated and uncoated fly ash concrete specimen were studied as pre- and post-exposed in seawater. Fly ash concrete coated with epoxy and acrylic had attained more strength compared to uncoated specimens. An increased strength in coated specimens and a decrease in value were observed in uncoated fly ash concrete specimens during split tensile strength. Coated specimens showed less reduction in pH value as compared to uncoated specimens. Rapid chloride permeability test (RCPT) analysis confirmed that epoxy and acrylic-coated concrete specimens appear to be denser than uncoated specimens leading to more resistance against the penetration of aggressive chemicals. The X-ray diffraction (XRD) comparative analysis of 56 and 90 days acrylic resin and epoxy resin-coated and uncoated specimen showed higher intensity in 90 days coated specimens than the uncoated specimens. Field emission scanning electron microscope (FESEM) investigation of uncoated 56 and 90 days concrete specimens subjected to seawater demonstrated dense appearance of hydrated products, whereas epoxy and acrylic-coated specimens were verified with no visible micro-cracks or holes on the surface, even at higher magnification. The epoxy and acrylic-coated fly ash concrete showed high physical strength and good bonding with concrete and will be appropriate for construction.
Show more [+] Less [-]Uncovering the dynamics in global carbon dioxide utilization research: a bibliometric analysis (1995–2019)
2021
Wong, Syie Luing | Nyakuma, Bemgba Bevan | Nordin, Abu Hassan | Lee, Chew Tin | Ngadi, Norzita | Wong, Keng Yinn | Oladokun, Olagoke
The anthropogenic emission of carbon dioxide (CO₂) into the atmosphere is recognized as the main contributor to global climate change. To date, scientists have developed various strategies, including CO₂ utilization technologies, to reduce global carbon emissions. This paper presents the global scientific landscape of the CO₂ utilization research from 1995 to 2019 based on a bibliometric analysis of 1875 publications extracted from Web of Science. The findings indicate a major increase in the number of publications and citations received from 2015 to 2019, denoting a fast-emerging research trend. The dynamics of global CO₂ utilization research is partly driven by China’s policies and research funding to promote low-carbon economic development. Applied Energy is recognized as a core journal in this research topic. The utilization of CO₂ is a multidisciplinary topic that has progressed by multidimensional collaborations at the country and organizations levels, while the formation of co-authorship networks at the individual level is mostly influenced by the authors’ affiliations. Keyword co-occurrence analysis reveals a rapid evolution in the CO₂ utilization strategies from chemical fixation in carbonates and epoxides to pilot-scale testing of power-to-gas technologies in Europe and the USA. The development of efficient power-to-fuel technologies and biological utilization routes (using microalgae and bacteria) will probably be the next research priorities in CO₂ utilization research.
Show more [+] Less [-]Study on the correlation of bisphenol A exposure, pro-inflammatory gene expression, and C-reactive protein with potential cardiovascular disease symptoms in young adults
2021
Tsen, Chao-Ming | Liu, Jia-Hong | Yang, Da-Peng | Chao, How-Ran | Chen, Jyh-Larng | Chou, Wei-Chun | Ho, Yi-Chen | Chuang, Chun-Yu
Bisphenol A (BPA) is a plasticizer used in the manufacture of polycarbonate and epoxy resins. It was found that higher urinary BPA levels are more likely to be associated with coronary artery disease (CVD). In recent years, the increasing incidence of CVD among young people is observed, which may be related with inflammation rather than the traditional triple-H risk factors. BPA is an endocrine-disrupting chemical, and can induce oxidative stress and chronic inflammation since its estrogenic effect. Inflammatory responses could come from the stimulation of IκB kinases (IKKs) by estrogen receptors (ERs). Therefore, this study investigated the association of BPA exposure with the gene expression of pro-inflammatory response (ERs and IKKs), an inflammation biomarker of CVD (C-reactive protein, CRP), and physiologic index potency of CVD development symptoms in young adults. This study divided BPA exposure levels into high and low groups based on the median plasma BPA level (4.34 ng/mL), and found that the high BPA group obviously had higher BMI, blood pressure, plasma CRP levels, and gene expression of ERβ and IKKβ. BMI and gene expression of IKKβ were also positively correlated with plasma CRP secretion. Furthermore, the study subjects with potential CVD development symptoms had the increased levels of BPA (OR 2.10, 95% CI 0.83–5.39), CRP (OR 2.61, 95% CI 1.03–10.6) and IKKβ (OR 4.29, 95% CI 1.51–15.6). These results indicated that exposure to BPA is potentially associated with expression of pro-inflammatory genes related to CRP secretion, which may promote the risk of CVD development symptoms in young adults. This study highlighted the possible connection between BPA exposure and CVD development but the mechanism between them needs to be further explored.
Show more [+] Less [-]Removal of color from real textile dyeing effluent utilizing tannin immobilized jute fiber as biosorbent: optimization with response surface methodology
2021
Rāẏa, Aparṇā
The present study explored an efficient technoeconomic method for treating intensely colored dyeing effluents from a commercial source. Firstly, the adsorption efficacy of jute fiber (JF) was enhanced through grafting with tannin, a natural polyphenol, via incorporation of active epoxy groups by epichlorohydrin onto fiber surface. The effect of different experimental parameters (e.g., initial pH, adsorbent dose, temperature, and contact time) on extent of color removal was evaluated performing batch studies. A full factorial central composite design (CCD) in response surface methodology (RSM) was applied to optimize the decolorization process for achieving maximum color removal (99.5%) at pH 4.9, adsorbent dose 11.8 g/L, temperature 30 °C, and time of contact 117.8 min. The isotherm and kinetic studies of the process revealed that Langmuir model and pseudo-second-order model provided best fit, yielding high correlation coefficients (R² > 0.997). Significant desorption (76%) of the spent adsorbent by 0.1 M NaOH solution suggested that this tannin-modified JF can find a prospective practical application as a novel, inexpensive, and potential bioadsorbent to treat the dyeing effluent.
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