Natural oil sorbents modification methods for hydrophobicity improvement

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International Scientific Conference “Environmental and Climate Technologies”, CONECT 2018 International Scientific Conference “Environmental and Climate Technologies”, CONECT 2018

Natural oil sorbents modification methods for The 15th International Symposium on District Heating and Cooling Natural oil sorbents modification methods for hydrophobicity improvement improvement Assessing the hydrophobicity feasibility of using the heat demand-outdoor Egle Anuzyte*, Vaidotas Vaisis

temperature functionEgle forAnuzyte*, a long-term district Vaidotas Vaisis heat demand forecast Vilnius Gediminas Technical University, Sauletekio al. 11, Vilnius, LT-10223, Lithuania Vilnius Gediminas aTechnical University, a,b,c a Sauletekio al. 11,bVilnius, LT-10223, Lithuania c

I. Andrić

*, A. Pina , P. Ferrão , J. Fournier ., B. Lacarrière , O. Le Correc

a

IN+ Center for Innovation, Technology and Policy Research - Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal Abstract b Veolia Recherche & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France Abstract c Département Systèmes Énergétiques et Environnement - IMT Atlantique, 4 rue Alfred Kastler, 44300 Nantes, France In recent years, accidental and intentional oil discharges have been occurred frequently during transportation, production, and refining, in severe negative impact on organisms and ecological environment. Among existing techniques for and the In recent which years, results accidental and intentional oil discharges have been occurred frequently during transportation, production, removal of oil from water, the use of sorbents is generally considered to be oneenvironment. of the most efficient techniques. Moreover, refining, which results in severe negative impact on organisms and ecological Among existing techniques for the application of natural sorbent is an attractive method for combating oilofspill mainly due to the lower costs, removal of oil from water, thematerials use of sorbents is generally considered to be one the pollution, most efficient techniques. Moreover, the Abstract high effectiveness and sorbent their properties as attractive reusability, biodegradability and recovery. Hydrophobicity is one of application of natural materialssuch is an method for combating oil spill pollution, mainly (oleophilicity) due to the lower costs, the major determinants of sorbents properties influencing the effectiveness of oil sorption in the presence of water. In order to high effectiveness and their properties such as reusability, biodegradability and recovery. Hydrophobicity (oleophilicity) is one District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing of the improve these properties, the surface of the sorbent is modified using chemical or physical treatment methods. The purpose of the major determinants of sorbents properties influencing the effectiveness of oil sorption in the presence of water. In order to greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat this study is to toproperties, analyze sorbents modification methods in orderrenovation to increase theirorhydrophobic-oleophilic characteristics for oil improve these the climate surface of the sorbent modified using chemical physical treatment methods. The purpose of sales. Due the changed conditions andisbuilding policies, heat demand in the future could decrease, spills cleanup intosorbents account environmental aspects. this to research organic sorbent – moss characteristics was treated with this study is the totaking analyze methods in In order increasenatural their hydrophobic-oleophilic for hot oil prolonging investment return modification period. water (80 °C and 100this °C), mercerized, coated withaspects. oil and in emulsions concentrations % and %.heat The testhot of spills cleanup taking into account In thiswater research naturalwith sorbent – 10 moss was50 treated with The main scope of paper is to environmental assess the feasibility of oil using the heat demand –organic outdoor temperature function for demand diesel sorption capacity was performed to compare the hydrophobic properties of modified sorbents. The results of this research water (80 °C and 100 °C), mercerized, coated with oil and oil in water emulsions with concentrations 10 % and 50 %. The test of forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 demonstrate that simple hotperformed water andto alkali can Three alterproperties the surface characteristics of The plant fibers improve diesel sorption capacity was compare thetypology. hydrophobic ofscenarios modified sorbents. results of and this research buildings that vary in both construction periodtreatments and weather (low, medium, high) and three district absorption demonstrate that simple hotdeveloped water and(shallow, alkali treatments candeep). alter To the estimate surface characteristics of plant improve renovationcapacity. scenarios were intermediate, the error, obtained heat fibers demandand values were absorption capacity. compared with results from a dynamic heat demand model, previously developed and validated by the authors. ©The 2018 The Authors. Published by Elsevier Ltd. results showed that when by only weatherLtd. change is considered, the margin of error could be acceptable for some applications © 2018 The Authors. ) This iserror an open accessPublished article under the CCthan BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/ ©(the 2018 The Authors. Published by Elsevier Elsevier Ltd. in annual demand was lower 20% for license all weather scenarios considered). However, after introducing renovation This is an open access article under the CC BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review responsibility of the scientific committee of the International Scientific Conference ) This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/ scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). Selection and peer-review under responsibility of the scientific committee of the International Scientific Conference ‘Environmental ‘Environmental and Climate Technologies’, CONECT 2018. Selection and peer-review under responsibility of the scientific committee of the International Scientific Conference TheClimate value of slope coefficient increased and Technologies’, CONECT 2018.on average within the range of 3.8% up to 8% per decade, that corresponds to the ‘Environmental Climate Technologies’, decrease in theand number of heating hours ofCONECT 22-139h 2018. during the heating season (depending on the combination of weather and Keywords: oil scenarios spills; oil spills cleanup methods; sorption; organicintercept sorbent; hydrophobicity; modification methods; renovation considered). On the sorbent; other hand, function increased for sorbent 7.8-12.7% per decade (depending on the environmentally friendly modification methods sorbent; sorption; organic sorbent; hydrophobicity; sorbent modification methods; Keywords: oil spills; oil spills cleanup methods; coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and environmentally friendly modification methods improve the accuracy of heat demand estimations.

© 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and * Corresponding author. Cooling.

E-mail address:author. [email protected] * Corresponding E-mail address: [email protected] Keywords: Heat demand; Forecast; Climate change 1876-6102 © 2018 The Authors. Published by Elsevier Ltd. This is an open access under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) 1876-6102 © 2018 Thearticle Authors. Published by Elsevier Ltd. Selection under responsibility of the scientific of the International Scientific Conference ‘Environmental and Climate This is an and openpeer-review access article under the CC BY-NC-ND licensecommittee (https://creativecommons.org/licenses/by-nc-nd/4.0/) Technologies’, CONECT 2018. Selection and peer-review under responsibility of the scientific committee of the International Scientific Conference ‘Environmental and Climate 1876-6102 © 2017 The Authors. Technologies’, CONECT 2018. Published by Elsevier Ltd. 1876-6102  2018 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of the International Scientific Conference ‘Environmental and Climate Technologies’, CONECT 2018. 10.1016/j.egypro.2018.07.095

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Egle Anuzyte et al. / Energy Procedia 147 (2018) 295–300 Author name / Energy Procedia 00 (2018) 000–000

1. Introduction Oil is one of the most important raw material used in chemicals and synthetic polymers production or in other industry areas. Oil spills is quite common accident, which can be caused by nature, such as earthquakes or hurricanes or human mistakes and negligence like vandalism or illegal discharge. Oil pollution does a lot of harm to nature, ecosystems, sea life also economy and tourism, the strong smell can be felt miles away and the extra growth of green algae alters the landscape [1]. There are various methods of oil spill cleanup, such as using in situ burning, booms, dispersants, marine bacteria and sorbent materials. Sorbent are materials that have the affinity to sorb, evenly distribute and trap liquid oil within their unique structure [2]. Recently the attention is given to agro-based natural sorbents, because they are environmentally friendly, non-toxic, degradable and inexpensive materials and usually are abundant in nature. Hydrophobicity is one of the main sorbent characteristics which describes the efficiency of oil sorption from the water surface. Hydrophobic-oleophilic properties depends on the chemical constituent of the sorbent, the amount of the surface wax, the physical configuration of the fiber, the twists and the crimps, surface roughness and its porosity. These characteristics also depends on the oil properties like concentration, specific gravity, temperature and the amount of the oil [3, 4]. Natural organic sorbents are mainly comprised of carbon (C), hydrogen (H), oxygen (O) and nitrogen (N) in the form of cellulose, hemicellulose, and lignocellulose [5]. Cellulose fibers can be effective when sorbs oil, but the hydroxyl groups (OH) located on its surface provides hydrophilicity, which can limit its application for oil cleanup from water. By replacing the OH groups, the surface of sorbent could be modified and become more hydrophobic [6]. Modification can improve fibers strength, dimensional stability, decay resistance, eliminate the moisture absorption of cellulose. It also provides a possibility for the development and application of the biomass wastes and these modifications on cellulosic materials for absorbing oil could be expanded to a level of industrial production [2]. Modification of sorbent can be done using physical and chemical methods. Therefore, while using natural and eco-friendly sorbents, improvement of their properties using eco-friendly techniques should be considered. 2. Sorbents modification methods Surface modification of sorbents can be carried out by a number of methods using physical and chemical modification. Most of the chemical treatments involve mercerization, acetylation, benzoylation treatment, grafting and others. 2.1. Physical modification methods Physical modifications like mechanical pressing or grinding affects the oil removal efficiency, but have no impact on hydrophobicity improvement of the natural sorbent. Organic sorbent which is grinded, demonstrates high oil sorption capacity and the reason is that sorbent contact surface is more available and binding sites are more accessible on smaller sorbent particles. Packing density properties are improved if sorbent materials are mechanically pressed and the higher packing density, the higher dynamic oil retention capacity of the sorbent can be determined. Therefore, sorbent which has high packing density oil sorption capacity is lower than the sorbent with low packing density [7, 8]. Low temperature thermal treatments like thermal bonding and drying don’t increase hydrophobicity and oil sorption capacity of organic natural sorbent comparing with raw fibre [9]. Otherwise, high temperature thermal treatment like pyrolysis is very efficient in increasing these certain properties of the sorbent. Angelova et al. obtained complex C-SiO2 containing material by carbonisation of rice husks at a temperature of 480 °C. Modifying the rice husk by pyrolysis showed better buoyancy characteristics, high oil sorption capacity and high hydrophobicity of the sorbent [10]. However, carbonization through pyrolysis is a costly and time-consuming operation [11].



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2.2. Chemical modification methods It is notorious, that cellulosic-based natural materials can be selected as cheap sorbents and their performance in removing oil from water surfaces can be enhanced using chemical modification. Generally, sorbents which are treated chemically, exposes lower water sorption and higher oil sorption capacities compared with unmodified ones. Numerous methods have been investigated with regard to improve sorbents hydrophobic and oleophilic properties. Most of the chemical surface treatments of sorbent include mercerization, acetylation, benzoylation, coupling agents, grafting and others [12]. Functional groups of various chemicals may be attached to hydroxyl groups, which are on the cellulose chain (in the The b-D glucopyranose) through a variety of reactions. The chemicals which are common used for the modification includes alkali, acetylation, benzoylation, acrylation and grafting, coupling agents, peroxide, stearic acid, fatty acid derivate (oleoyl chloride) and others. Researchers are using these methods in order to prepare sorbent materials for oil cleaning application: esterification, etherification, halogenations, oxidation, alkali treatment, mercerization, acetylation, benzoylation, peroxide and coupling agents with or without heat are widely being applied to change sorbent surface [13, 14]. 2.3. Environmentally friendly modification methods Although physical and chemical hydrophobizing treatments can alter the wettability of plant fibres, they are useful and acceptable in diversified applications, these methods have disadvantages. However, physical treatment methods like pyrolysis demands a lot of time and it is costly. Chemical methods involve a lot of hazardous chemicals in the process pre-treatment of plant fibres, which is not biodegradable and it is waste. Proper handling and disposal of chemical waste increases process cost. Therefore, surface modification of plant fibres using chemical treatments can be avoided by alternative methods. Instead, efforts should be focused on environmentally friendly methods to increase the hydrophobicity and oleophilicity of plant fibres [12]. Environment friendly methods such as plasma treatment, hot water treatment, lignin coating, treatments using bacteria, surface modification with plant triglycerides can be used for the surface modification of plant fibres [12, 15–18]. 3. Methodology of sorbents experimental research For this investigation sorbent – moss species Rhytidiadelphus triquetrus is used to evaluate treated sorbent sorption properties such as diesel sorption capacity. Natural organic sorbent was treated with different solvents in order to improve its hydrophobic properties. Moss were treated with alkaline solution such as NaOH (5 %), hot water (80 °C and 100 °C), coated with oil and oil in water emulsions with concentrations 10 % and 50 %. Untreated and treated samples were air dried and then dried in oven at 110 °C till they reached constant weight. After the treatment sorbents were placed in dry zipped bags for the oil sorption capacity test. 3.1. Treatment of the Sorbent  Sorbent Mercerization – treatment with NaOH solution. In order to determine if the environmental friendly modification method is efficient, comparison with most commonly used method is needed. Mercerization – alkaline chemical treatment is one of the most popular organic sorbent modification method. This method is widely used in literature, because it is simply and effective way [6, 18];  The sample was placed into NaOH solvent (5 %) in a glass flask and shaked in a room temperature (25 °C) for 48 h. When the treatment was completed, the obtained sample was drained and then dried in an oven at 110 °C for 24 h. The methodology was used from the research done by Wong et al. [18];  Hot water treatment. Sorbent treatment with hot water process removes extractives, volatile compounds and waxy coatings from cellulosic fibres, that increases better accessibility for the absorption medium. For hot-water treatment, dried sorbent was immersed in deionized (DO) water at temperatures 80 °C and 100 °C for 1 h. After the 1 h immersion, the fibres were air dried and oven-dried at 110 °C for 24 h;

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 Surface modification with plant triglycerides. Sorbent was coated with oil in aqueous emulsions. Refined and deodorized rapeseed oil was used in this research. Rapeseed oil global production is about 12.6 % from all other global production of oils. The ratio of unsaturated and saturated fats of rapeseed oil is 24 and total unsaturated fats in the oil amounts to 96 %. This kind of oil consists of saturated palmitic, stearitic fats, monosaturated-oleic, gondoic, erucic fats and polyunsaturated-linoleic and α-Linoleic fats. To saturate the cellulose material, excess oil solution was applied with twice the mass of oil solution to the sorbent mass. Aqueous emulsions with 10 % and 50 % concentrations were prepared with addition of a non-ionic surfactant (0.4 %). Oil without water was delivered to the sorbent surface without the help of surfactant – spraying the rapeseed oil on the sorbent. Following oil applications, all samples were dried under the ambient temperature then heated at 110 °C for 24 h. 3.2. Methodology of sorbent sorption properties In order to evaluate if modified sorbents hydrophobicity is improved, oil sorption capacity test was investigated according to the Standard Test Method for Sorbent Performance of Adsorbents (ASTM F726-12). In this research loosed-form moss parts (size 3–10 mm) were packed inside wire-mesh basket and immersed inside a beaker filled with liquid (Fig. 1(a)). In oil sorption capacity test, beaker was filled with 800 ml of tap water and 80 ml of diesel was poured on the top. Such a quantity of diesel was chosen based on the sorbent height so that the entire area of the sorbent surface is accessible to the oil. Weight of sorbent after treatment was different due to different treatments, however amount of sorbents was used by visible determination to cover surface area inside the beaker with liquid, not taking mass in to account. Mesh with the sorbent was taken out from the beaker after 1 h, excess liquid was removed by keeping the mesh with the sorbent for 2 min above the beaker (Fig. 1(b)). Experiment was repeated three times.

(a)

(b)

Fig. 1. Oil sorption test: (a) beakers filled with liquid and sorbent with the mesh; (b) liquid excess elimination.

Oil absorbency is the amount of investigative liquid absorbed of 1 g of sorbent (Eq. (1)): M Oil 

where MOil M1 M2 MS

(M 1  M 2 ) MS

(1)

liquid absorption, g/g; weight of the beaker with the liquid before the mesh with sorbent immersion, g; weight of the beaker with the liquid after the mesh with sorbent immersion, g; weight of the sorbent, g.

The uptake capacity is referred to as the absorbency ratio and is reported as the mass of liquid uptaken per mass of sorbent (g/g).



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Oil absorbency test was made in the ambient room temperature (20 ± 2 °C). For oil sorption – diesel was used. Diesel density at 20 °C is 0.826 g/cm3 and viscosity – 4.46 cSt. 4. Results and discussion Using method by ASTM F726-12 standard, diesel sorption capacity of each type of sorbent was investigated and the results are shown in the table below, where M1 is the amount of diesel absorbed by the sorbent mass, g; MS – a weight of the sorbent, g; MOil is diesel absorption, g diesel/g sorbent. Table 1. Diesel sorption capacity of each type treated sorbent, values are shown as the mean ± standard deviation. Sorbent treatment type

MS, g

M1, g

MOil, g/g

Hot water treatment at 100 °C

0.85

6.70

7.85 ± 0.09

Hot water treatment at 80 °C

0.81

6.67

8.27 ± 0.06

Coating with oil-water emulsion, 10 % concentration

2.13

6.18

2.90 ± 0.12

Coating with oil-water emulsion, 50 % concentration

4.42

7.18

1.62 ± 0.11

Coating with oil without water

4.48

4.86

1.09 ± 0.06

Mercerization (NaOH)

0.65

5.87

8.99 ± 0.08

Untreated sorbent

0.78

5.71

7.36 ± 0.09

As shown in Table 1, the biggest amount of diesel was absorbed by 1 g of sorbent treated with NaOH (5 %) solution. Mercerization caused swelling and increased the surface area and roughness of moss fibres, what enhanced diesel sorption capacity by 22 %. Treating sorbent with hot water at 100 °C and at 80 °C temperatures increased sorbent sorption capacity. Sorbent heated in the 80 °C temperature water showed better results than in 100 °C temperature water – sorption capacity increased by 12.4 %, while heating at 100 °C water, diesel sorption capacity increased by 6.7 %. Hot water treatment at 80 °C temperature was enough to remove volatile compounds and the waxing coating of the moss surface, which made it more accessible to the sorption media. This coarser and undulant surface cannot only increase the surface area of the fibre but also improves the adhesion of oil on fibre surface [16]. Results of coating the fibre with oil showed the reduction of diesel sorption capacity. Immersion of sorbent in oil and water emulsions at concentrations of 10 % and 50 % reduced the absorption of diesel by 60.6 % and 78.0 %, respectively. Modified moss which is coated with oil not in aqueous emulsion showed the lowest diesel penetration capacity, it is reduced by 85 % and is almost 8 times lower. It is evident that the higher the amount of oil on the moss surface – the lower diesel sorption capacity. This might have happened because the biggest part of sorbent area was coated and sorbent pores were filled with the rapeseed oil, which resulted decreased diesel adhesion with the surface and the lowest diesel penetration into the pores from all the investigated modified sorbents. 5. Conclusions  The hydroxyl functionality of fibres can be reduced by physical and chemical modifications. The main routes of direct cellulose modification in the preparation of sorbent materials are esterification, etherification, halogenations, oxidation, alkali, surfactant treatment, mercerization, acetylation, benzoylation, peroxide and coupling agents with or without heat are widely being applied to modify fibre surface. Physical modification such as pyrolysis is used;  Surface modification of plant fibers using chemical treatment can be avoided by alternative methods. Environment friendly methods such as plasma treatment, hot water treatment, lignin coating, treatments using bacteria, surface modification with plant triglycerides can be used;

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 For this investigation sorbent – moss (species Rhytidiadelphus triquetrus) is used as one of natural and renewable material;  In order to improve sorbent hydrophobicity and oleophilicity for this experiment sorbent treatment methods were used: treatment with hot water (at 80 °C and at 100 °C), sorbent coating with oil – spraying it on the surface and treating with aqueous emulsions (10 % and 50 % concentrations) with addition of surfactant (0.4 %). Mercerization – alkaline chemical treatment with NaOH (5 %) is used to compare environmentally friendly methods with chemical treatment;  In order to evaluate if modified sorbent absorbency properties are improved, water and oil sorption capacity tests have to be performed. Water and oil sorption capacity tests are made according to ASTM F726-12 standard method, because it is the base method used by the researchers. For oil sorption – diesel was used;  There were varying responses to the different treatment method per sorbent. Mercerization, hot water treatment at 80 °C and hot water treatment at 100 °C exhibited the highest absorption capacity of diesel – 8.99 g/g 8.29 g/g and 7.85 g/g, respectively. Results were higher than untreated sorbents sorption capacity, which was 7.36 g/g. These methods caused the swelling of cellulose fibres, resulting an increase in the fibres sorption capacity due to increasing the surface area. Coating the surface with oil reduced diesel's penetration. References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18]

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