State of the art of the environmental behaviour and removal techniques of the endocrine disruptor 3,4-dichloroaniline

In recent years, the presence of Endocrine Disrupting Chemicals (EDCs) in wastewater discharges from agricultural and industrial sources, fresh- and estuarine-waters, as well as soils, has been reported in the literature. Studies of adverse changes in wildlife, linked to environmental exposure to these substances, and the suggestion that humans could also be at similar risk of adverse health effects, have raised concern for urgent action to understand and reduce such risks. 3,4-dichloroaniline (3,4-DCA) has been recognized as an EDC, with regards to endocrine disruption data for both wildlife populations and human health. 3,4-DCA is present in the environment as a product of the biodegradation of phenylurea and phenylcarbamate pesticides; furthermore, it can be introduced from industrial and municipal wastewater that is insufficiently purified, or via accidental spills. Increasing concentrations of 3,4-DCA in soil and water are the result of its high persistence and accumulation, as well as its low biodegradability. Hence, remediation techniques require in-depth study, especially when considering the low removal achieved by traditional activated sludge treatments, and the generation of carcinogenic trihalomethanes as a consequence of the chlorine oxidation methods frequently used in drinking water plants. Fe0/H2O2 systems, photodegradation using doped TiO2, and the use of dielectric barrier discharge reactors, seem to be the most promising techniques for the removal of 3,4-DCA from water

Terbuthylazine and desethylterbutylazine : recent occurrence, mobility and removal techniques

The herbicide terbuthylazine (TBA) has displaced atrazine in most of EU countries, becoming one of the most regularly used pesticides and, therefore, frequently detected in natural waters. The affinity of TBA for soil organic matter suggests prolonged contamination, once present; degradation leads to the release of the metabolite desethylterbuthylazine (DET), which has a higher water solubility and binds more weakly to organic matter compared to the parent compound, resulting in higher associated risk for contamination of groundwater resources. Additionally, TBA and DET are chemicals of emerging concern because of their persistence and toxicity towards aquatic organisms; moreover, they are known to have significant endocrine disruption capacity to wildlife and humans. Conventional treatments applied during drinking water production do not lead to the complete removal of these chemicals; activated carbon provides the greatest efficiency, whereas ozonation can generate by-products with comparable oestrogenic activity to atrazine. Hydrogen peroxide alone is ineffective to degrade TBA, while UV/H2O2 advanced oxidation and photocatalysis methods are the most effective processes for oxidation of TBA, with efficiencies above 90%. It has been determined that direct photolysis gives the highest degradation efficiency of all UV/H2O2 treatments, while most of the photocatalytic degradation efficiency is attributed to OH radicals, and TiO2 solar-photocatalytic ozonation can lead to almost complete TBA removal in ~30 min. Biomixtures could also be highly effective in preventing groundwater pollution due to TBA and DET, while constructed wetlands provide a valuable buffer capacity, protecting downstream surface waters from contaminated agricultural runoff

Organics adsorption on novel amorphous silica and silica xerogels : microcolumn rapid breakthrough test coupled with sequential injection analysis

The adsorption capacities of a novel amorphous silica and silica xerogels for aromatic compounds were investigated using microcolumn rapid breakthrough tests coupled with sequential injection flow-based automated instrumentation in order to evaluate their operative feasibility under conditions typically used in water treatment facilities. Extraction columns were fabricated using stereolithographic 3D printing. Sorbent reusability was also investigated using automated flow-based techniques. Benzene was selected as the target dissolved organic compound usually present in produced waters from the oil and gas sector, continuously increasing. 3,4-Dichloroaniline (3,4-DCA) was selected as part of the endocrine disrupting chemicals, which are becoming a source of major concern for human and wildlife toxicity. Novel amorphous silicas were synthesized at low temperature and under ambient pressure from a sodium metasilicate precursor and were subjected to postsynthetic methylation. Silica xerogels were prepared via acid catalysis of a sodium metasilicate solution and functionalized with trimethylchlorosilane at low temperature and under ambient pressure. The removal efficiency of the silica xerogels tested was found to be equal to or greater than 22.62 mg/g for benzene at a flow rate of 0.6 mL/min, while the uptake of 3,4-DCA was found to be > 4.63 and > 7.17 mg/g, respectively, at flow rates of 1.8 and 0.6 mL/min

Novel amorphous silica and silica xerogels for the adsorption of organic pollutants from water

This thesis was previously held under moratorium from 9th November 2017 until 9th November 2022.The demand on water supplies is becoming more intensive, thus the need for innovative and cost effective produced water treatment technologies is rising. Produced water is the largest by-product generated by oil and gas extraction, hence, there are significant quantities requiring remediation. Furthermore, over recent years, the presence of other organics known as Endocrine Disrupting Chemicals (EDCs) in various sewage discharges, fresh- and estuarine-waters, has been extensively reported, becoming an increasing source of concern. Membranes are a promising technology for water remediation and the use of an adsorption media as a prior treatment could make them a potentially cost-effective option. Among solid sorbents, hydrophobic aerogels exhibit attractive properties for oil spill applications; however, very few studies have investigated their adsorption performance at low organic concentrations and the cost of functionalisation of these materials, hinder their use as sorbents in the final stages of produced water treatments. This work studies the adsorption of benzene, toluene and the EDC 3,4-dichloroaniline (3,4-DCA) below their solubility limits on hydrophilic and hydrophobic samples of the novel amorphous silica Quartzene and on silica xerogels, synthesised by a low cost and environmentally friendly synthesis, inspired from the work of Bangi, Rao A.P., Hirashima and Rao A.V. [1]. All adsorbents used in this study were also characterised by SEM, FTIR and BET analysis. The full adsorption capacity of hydrophilic Quartzene was achieved in less than 10 h, with 70-90% of uptake in the first 6 h. Adsorption capacities were found to be up to 264 mg/g for benzene and 78.8 mg/g for toluene. Hydrophobic Quartzene, demonstrated an equilibrium value four times higher that of the hydrophilic analogue, reached in less than 3 h at a concentration of 200 ppm benzene. With regard to the synthesised xerogels, evaporation rates and the optimal combination of reactants were identified, in order to obtain the desired degree of hydrophobicity and a surface area mainly due to pores with sufficient dimension to allow pollutant penetration. The so synthesised xerogels adsorb dissolved benzene and 3,4-DCA from water, showing no damage of the granules after days of rotary stirring, suggesting potential re-use. The adsorption behaviour is described by a two-step mechanism, with equilibrium times of ~24 h, with adsorption capacities up to 75 mg/g for benzene and 12.5 g for 3,4-DCA. Micro Column Rapid Breakthrough tests coupled with Sequential Injection Analyses were also conducted, in order to obtain a preliminary evaluation of the adsorbents operative feasibility under conditions more similar to those typically used in water treatment facilities. Micro-columns were designed and 3D printed in methacrylate. Automated solid-phase extraction was used to verify desorption of the analytes by methanol injection. The removal efficiency of the hydrophobic sample of Quartzene was found to be >5.85 mg/g of benzene, with an initial concentration of 73.3 mg/L. The removal efficiency of the silica xerogels was found to be >22.62 mg/g for benzene, with an initial concentration of 105.12 mg/L; the corresponding uptakes of 3,4-DCA were found to be >4.63 mg/g and >7.17 mg/g, respectively, at flowrates of 1.8 mL/min and 0.6 mL/min and with an initial concentration of 16-20 mg/L. Higher removal efficiencies coupled with higher rate of adsorption, which would lead to lower Empty Bed Contact Times (EBCTs), would be required for all the sorbents tested here to be used for treatment of produced water prior to a membrane configuration, especially in offshore facilities. The rate of adsorption of 3,4-DCA, and the related adsorption capacity of the silica xerogels studied here could be promising for large scale application to removal of pesticides and other organic micropollutants, as filling of filters, cartridges or permeable reactive barriers.The demand on water supplies is becoming more intensive, thus the need for innovative and cost effective produced water treatment technologies is rising. Produced water is the largest by-product generated by oil and gas extraction, hence, there are significant quantities requiring remediation. Furthermore, over recent years, the presence of other organics known as Endocrine Disrupting Chemicals (EDCs) in various sewage discharges, fresh- and estuarine-waters, has been extensively reported, becoming an increasing source of concern. Membranes are a promising technology for water remediation and the use of an adsorption media as a prior treatment could make them a potentially cost-effective option. Among solid sorbents, hydrophobic aerogels exhibit attractive properties for oil spill applications; however, very few studies have investigated their adsorption performance at low organic concentrations and the cost of functionalisation of these materials, hinder their use as sorbents in the final stages of produced water treatments. This work studies the adsorption of benzene, toluene and the EDC 3,4-dichloroaniline (3,4-DCA) below their solubility limits on hydrophilic and hydrophobic samples of the novel amorphous silica Quartzene and on silica xerogels, synthesised by a low cost and environmentally friendly synthesis, inspired from the work of Bangi, Rao A.P., Hirashima and Rao A.V. [1]. All adsorbents used in this study were also characterised by SEM, FTIR and BET analysis. The full adsorption capacity of hydrophilic Quartzene was achieved in less than 10 h, with 70-90% of uptake in the first 6 h. Adsorption capacities were found to be up to 264 mg/g for benzene and 78.8 mg/g for toluene. Hydrophobic Quartzene, demonstrated an equilibrium value four times higher that of the hydrophilic analogue, reached in less than 3 h at a concentration of 200 ppm benzene. With regard to the synthesised xerogels, evaporation rates and the optimal combination of reactants were identified, in order to obtain the desired degree of hydrophobicity and a surface area mainly due to pores with sufficient dimension to allow pollutant penetration. The so synthesised xerogels adsorb dissolved benzene and 3,4-DCA from water, showing no damage of the granules after days of rotary stirring, suggesting potential re-use. The adsorption behaviour is described by a two-step mechanism, with equilibrium times of ~24 h, with adsorption capacities up to 75 mg/g for benzene and 12.5 g for 3,4-DCA. Micro Column Rapid Breakthrough tests coupled with Sequential Injection Analyses were also conducted, in order to obtain a preliminary evaluation of the adsorbents operative feasibility under conditions more similar to those typically used in water treatment facilities. Micro-columns were designed and 3D printed in methacrylate. Automated solid-phase extraction was used to verify desorption of the analytes by methanol injection. The removal efficiency of the hydrophobic sample of Quartzene was found to be >5.85 mg/g of benzene, with an initial concentration of 73.3 mg/L. The removal efficiency of the silica xerogels was found to be >22.62 mg/g for benzene, with an initial concentration of 105.12 mg/L; the corresponding uptakes of 3,4-DCA were found to be >4.63 mg/g and >7.17 mg/g, respectively, at flowrates of 1.8 mL/min and 0.6 mL/min and with an initial concentration of 16-20 mg/L. Higher removal efficiencies coupled with higher rate of adsorption, which would lead to lower Empty Bed Contact Times (EBCTs), would be required for all the sorbents tested here to be used for treatment of produced water prior to a membrane configuration, especially in offshore facilities. The rate of adsorption of 3,4-DCA, and the related adsorption capacity of the silica xerogels studied here could be promising for large scale application to removal of pesticides and other organic micropollutants, as filling of filters, cartridges or permeable reactive barriers

Leather tanning: Life cycle assessment of retanning, fatliquoring and dyeing

Tanneries boost the local economic development, but lead to severe environmental pollution; hence, improving the environmental assessment of this sector is essential. In this paper, the Life Cycle Assessment method was applied to estimate impacts on the environment and human health of retanning, fatliquoring and dyeing. The analysis was performed from a “gate to gate” perspective. Moreover, sulpho chlorinated paraffin and epoxidized vegetable oil have been evaluated as alternative fatliquoring agents. The production of electricity required for the rotation of drums gives the main contribute to most of the impact categories, followed by the azo-dye production. Emissions of sulfur dioxide, nitrogen oxides, manganese, vanadium and nickel associated to power plants are the main sources of terrestrial acidification and particulate matter formation, as well as of human and marine toxicity (4.48·10 −1 and 1.09·10 −2 kg of 1,4-DBeq kg −1 crust leather, respectively). Nitrate loads from wastewater treatment and oxidative treatments affect heavily marine eutrophication (6.9·10 −1 g N eq kg −1 crust leather). The use of epoxidized vegetable oil would affect human toxicity, ecosystem, metal and water resources depletion more than the use of sulpho chlorinated paraffin, mainly due to pesticides distribution and other cultivation practices. Phosphate and nitrate releases due to fertilization determine the high impact on the categories freshwater and marine eutrophication. Progress in increasing the conversion efficiency is demanded, but overall focus must be made on the substitution of fossil fuels with cleaner alternatives. The transition towards a circular economy is encouraged; increasing rates of reduction, reuse, recycle and recover of solid waste and tannery effluents are recommended. Agricultural practices with a reduced consumption of phytosanitary products and mineral fertilizers, alternative to conventional farming, would strongly contribute to increase the sustainability of epoxidized vegetable oil as alternative fatliquoring agent

Environmental sustainability of agri-food supply chains: An LCA comparison between two alternative forms of production and distribution of endive in northern Italy

Alternative cultivation practices such as organic and integrated farming are generally proposed as a mean to reduce environmental impacts associated with food production and consumption. For the same reason, various schemes of direct sale or distribution of local agricultural products have been increasingly developed as an alternative to large-scale distribution of nationally or globally sourced products. However, for a variety of vegetable crops such as salads and leaves, there is few scientific evidence about the relative environmental performance of alternative farming techniques. Similarly, alternative distribution systems have mainly been investigated only in terms of their energy and climate change performance, and mostly within the debate on domestic/local versus imported/delocalised food supply. In this paper, life cycle assessment (LCA) was used to compare the potential environmental impacts of two agricultural supply chains, with the primary aim of testing the expected benefits of vegetable organic farming and of alternative forms of distribution promoting packaging reduction and a shortened supply chain. Organic and integrated production of endive (Cichorium endivia) in Lombardia (northern Italy) were firstly compared, according to a cradle-to-farm gate approach. The comparison was then extended to the whole supply chain, considering the direct distribution of raw organic endive to local networks of ethical purchasing groups by means of returnable crates, and the large-scale retailing of conventional endive as a ready-to-use product after its industrial cutting, washing and packing. Fourteen environmental and human health impact categories were considered as terms of comparison, along with the cumulative energy demand. Results revealed that none of the examined farming techniques has a better overall environmental profile. In fact, when impacts are expressed per hectare of cultivated area, nearly half impact categories (7/15) are favourable to organic farming, with impact reductions ranging from 13% to 55%. However, organic fertilisation practices are responsible for higher impacts of this cultivation form in terms of acidification (+16%), terrestrial eutrophication (+32%) and non-carcinogenic human toxicity (+127%). Per kg of harvested product, impact categories favourable to organic farming are reduced to five, while six are favourable to integrated farming (which achieves higher yields). Organic farming techniques thus need to be further improved in terms of fertilisation practices and achievable yields in order to achieve a more sustainable production system. Considering the whole supply chain, the direct distribution of the raw organic product loose at the local level is preferable for all impact categories except one, where the impact of the farming stage is dominant and against organic production. This exception however disappears if farming is excluded from the comparison (i.e. only distribution and consumption are considered). Observed reductions in overall supply chain impacts range mostly between 20% and 48% and are mainly enabled by the absence of disposable packaging items and industrial processing

Novel hydrophilic and hydrophobic amorphous silica : Characterization and adsorption of aqueous phase organic compounds

Very few studies have investigated the adsorption performance of hydrophobic and hydrophilic silicas with dissolved organics in water, which is a required final step during produced water treatment. The cost of functionalization also hinders the use of hydrophobic materials as sorbents. Novel hydrophilic silicas, prepared at low temperature and ambient pressure, were characterised by SEM, FTIR and BET analysis, and studied for the adsorption of aqueous phase organic compounds at concentrations below their solubility limits. Adsorption capacities were found to be up to 264 mg/g for benzene and 78.8 mg/g for toluene. Direct comparison is made with the analogous hydrophobic version of one of the silica materials, demonstrating comparable uptakes for benzene concentrations lower than 50 mg/L. This finding supports the hypothesis that, at very low aqueous phase organic concentrations, hydrophobicization has no discernible effect on access of the pollutants to the internal porosity of the material

Pollutant removal from gaseous and aqueous phases using hydrochar-based activated carbon

In this study, hydrochar (HC) produced at industrial scale by hydrothermal carbonization of municipal woody and herbaceous prunings was used for producing activated carbon by KOH chemical activation. Different KOH/HC ratios were studied to produce highly porous materials with high surface area. Activated carbon with a BET surface area up to 1739 m2/g was obtained for a 3:1 KOH/HC ratio. Adsorption properties of obtained samples were studied for removing pollutants both from gas and liquid phases. Thermogravimetric analyzer (TGA) was used for evaluating the removal capacities of CO2from a gaseous phase, while UV-Vis spectroscopy was used for evaluating the removal capacities of an emerging contaminant from an aqueous phase. All samples showed a good CO2adsorption capacity at 27 °C, reaching 84.5 mg CO2/g sorbent for hydrochar activated with an impregnation ratio of 2:1. Moreover, activated chars exhibited a high removal efficiency (up to 97.9 % for a 3:1 KOH/HC ratio) for atrazine, which is one of the most common pesticides detected in superficial and groundwater aquifers