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Phytoremediation of Heavy Metals-Polluted Soil
Published in Pankaj Chowdhary, Abhay Raj, Contaminants and Clean Technologies, 2020
Amjad Ali, Di Guo, Amanullah Mahar, Fazli Wahid, Parimala Gnana Soundari Arockiam Jeyasundar, Muhammad Azeem, Ronghua Li, Zengqiang Zhang
Natural chelating agents such as EDDS and nitrilotriacetic acid (NTA) are alternatives to EDTA. But they also have leaching and toxicity effects on plants. Thus, proper care should be taken when practicing induced phytoremediation (Evangelou et al., 2008; Song et al., 2012). At the phytotoxic level of metals in the soil, lime and organic matter can be the best choice for delaying solubility. The use of citric acid as a chelating agent could be promising because it has a natural origin and is easily biodegradable in soil. Furthermore, citric acid is nontoxic to plants, and therefore, plant growth is not restricted (Smolińska and Cedzyńska, 2007). Chelates can be particularly useful in mobilizing HMs at high soil pH as the stability of metal–organic complex increases with increasing pH. The common chelates used for enhancing the HMs (Cd, Pb) phytoremediation are presented in Table 13.3.
Prussian Blue for Battery Electrodes
Published in Yannick Guari, Joulia Larionova, Prussian Blue-Type Nanoparticles and Nanocomposites, 2019
Manabu Ishizaki, Masato Kurihara
Citric acid is a common reagent for the syntheses of metal NPs [113–115], acting as a reducing agent of metal ions and a surface-stabilizer for metal NPs. Citric acid and its compounds have been applied to food and pharmaceuticals because of low toxicity [116, 117]. The citrate-modified metal NPs usually are stably dispersed into water by their negative surface charges [118]. PB and PBAs have been explored in a range of bio-applications. Currently, the non-toxic water dispersible NPs are required: Since 2010, the water ink of the citrate-modified PB NPs has been continuously reported (Fig. 7.17), and been availed as such bio-probes and magnetic resonance imaging agents (MRI) [119, 120]. In a typical synthesis, an aqueous solution (20 mL) of FeCl3 (1.0 mM) containing citric acid (0.5 mmol) was added to an equimolar aqueous solution of K4[Fe(CN)6] containing citric acid (0.5 mmol) with vigorous stirring at room temperature, and the solution color was immediately changed to blue. After adding acetone to the blue solution, the blue pigment was isolated by centrifugation. The XRD patterns of the blue pigment showed the cubic face-centered structure of PB. A TEM average particle size was 13 ± 5 nm. The citrate-modified PB NPs can be re-dissolved into water [121], and have been widely used such as photo-device consisting of a PB thin film [122] and a bio-probe using the dye-connected PB NPs [119, 120].
Impact of Well Remediation Chemicals on Water Quality and Deterioration
Published in Joseph A. Cotruvo, Gunther F. Craun, Nancy Hearne, Providing Safe Drinking Water in Small Systems, 2019
Citric acid (C6H8O7) is a dry organic acid that is safe to handle. It also has a chelating effect for the control of trace metals in the well and is effectively applied at % pound of dry acid per gallon of water in the well. Citric acid is effective alone or in combination with other cleaning chemicals or acids. Add low dosages prior to shock chlorination to stabilize water (at pH 6 to 7) for most effective disinfection rates. Jar testing of well water determines exact dosage requirements for mild pH adjustment.
Chelate assisted phytoextraction for effective rehabilitation of heavy metal(loid)s contaminated lands
Published in International Journal of Phytoremediation, 2023
Akshaya Prakash Chengatt, Nair G. Sarath, Delse Parekkattil Sebastian, N. Shibin Mohanan, E. S. Sindhu, Satheesh George, Jos T. Puthur
Low molecular weight organic acids occur naturally in soil and are derived from the decomposition of soil organic matter, microbial metabolites, plant root exudates, etc. (Qin et al.2004; Taghipour and Jalali 2013). These acids include citric acid, oxalic acid, formic acid, butyric acid, succinic acid, malic acid, and acetic acid (Xiao and Wu 2014). Citric acid is a naturally occurring organic compound produced using yeasts and fungi by fermentation and citrus fruit extraction (Khadir 2011; Bera et al.2013). It can be used as a green chelating agent for eliminating heavy metals from the polluted matrix. This property of chelation and extraction efficiency showed its maximum at a pH of 2.3 (Del-Dacera and Babel 2006; Huang et al. 2008; Niinae et al.2008). Similarly, oxalic acid is a low molecular weight natural organic acid and green chelating agent with moderate metal chelating capacity. Low molecular weight organic acids are advantageous over APCAs due to their biodegradability, less tenacity in the environment, and good potential for enhancing phytoremediation (Evangelou et al.2007).
Fabrication and characterization of dual-layer hollow fibre membranes incorporating poly(citric acid)-grafted GO with enhanced antifouling properties for water treatment
Published in Environmental Technology, 2023
Noresah Said, Woei Jye Lau, Muhammad Nidzhom Zainol Abidin, Amir Mansourizadeh, Ahmad Fauzi Ismail
Since citric acid comes from fruits and veggies, it is generally safe for use. Besides, citric acid is a very cheap material compared to other materials typically used to modify GO including polydopamine and silane coupling agents. Based on the literature, citric acid-functionalized GO was only studied for dye removal by adsorption [27], catalytic reaction process [28] and flat sheet composite membrane [29]. Thus, the novelty of this work is to study the impacts of citric acid-functionalized GO on the DLHF membranes for the UF process. Before DLHF membrane fabrication, the effect of nanomaterial loading on the properties of the membrane was first studied in the SLHF membrane to obtain the best loading to be used for the DLHF membrane. The effect of nanomaterials on the DLHF membrane was then investigated for morphology, water permeability, solute separation and antifouling performance.
Fabrication of Antheraea mylitta sericin hydrogel film via non toxic crosslinking citric acid with antioxidant properties
Published in Soft Materials, 2023
Sheela Khanapure, Ankith Sherapura, Prabhakar B T, Shyam Kumar Vootla
Hence, we have constructed a novel nontoxic Antheraea mylitta sericin hydrogel film by blending with and without polyethylene glycol (PEG), a nontoxic, US Food and Drug Administration (FDA)-approved hydrophilic, amphipathic polymer with several properties ideal for biomedical and biotechnical applications[23] and crosslinking with citric acid. Earlier reported hydrogels were fabricated by blending or copolymerizing with synthetic polymer polyvinyl alcohol,[24] and several other biopolymers such as carboxymethyl cellulose,[25] chitosan,[26] gelatin,[9] and collagen,[27] and are crosslinked either with glutaraldehyde or with genipin. These crosslinking agents are known to be cytotoxic.[28] Whereas citric acid is an FDA-approved nontoxic, cost-effective, organic, weak tricarboxylic acid. The carboxylic and hydroxyl groups present in citric acid allow crosslinking of various polymers[29–31] and are known to enhance the functionality of the biomaterials crosslinked through citric acid in terms of stability, hydrophilicity, controlled swelling behavior, hemocompatibility, and cytocompatibility.[28] Currently, various crosslinkers are used for silk biomaterial processing, whereas citric acid has been used for either degumming of sericin[32] or improving silk fabrics quality,[33] but there are no standard reports on using citric acid for crosslinking of sericin biopolymer for fabrication of biomaterials.