Grafting yield determination of glycidyl methacrylate vapor on radiated kenaf fiber via FTIR spectroscopy

In this study, glycidyl methacrylate (GMA) was grafted onto kenaf fiber using radiation-induced graft polymerization technique in vapor phase. The pre-irradiation of kenaf fiber was carried out at different doses from electron beam accelerator at various absorbed radiation doses (10 to 100 kGy). The grafting process was carried out in a vapor-phase graft polymerization reactor operated at temperature of 40 °C. The grafted chains were verified with FT-IR spectroscopy analysis. The percentage of grafting, Pg (%) of the grafted kenaf fiber was calculated based on quantitative Fourier transform infra-red spectroscopy (FTIR) analysis. Functional group present onto the kenaf fiber backbone after grafting was used to quantify the unknown amount of GMA grafted to the kenaf fiber and to calculate the Pg (%). Characteristic peak of 1725 cm-1 corresponding to the carbonyl group of GMA was chosen for calibration purpose in order to derive a linear regression plot of peak area versus the weight per volume percent of GMA (w/v%). The correlation coefficient for the calibration line is 0.967, which indicates that the correlation between absorbance and concentration is good. It was observed that grafting of vapor GMA onto pre-irradiated kenaf fiber reach the maximum yield of 191.89% with the absorbed radiation dose of 50 kGy

Adsorption studies of packed bed column for the removal of dyes using amine functionalized radiation induced grafted fiber

In this paper, the adsorption performance of packed bed column with amine functionalized radiation-induced grafted fibers (AFF) for the removal of acid blue 80 (AB 80) was investigated. Pretreated banana fibers were grafted with glycidyl methacrylate (GMA) with the assistance of electron beam irradiation and subsequently functionalized with imidazole, which was used as the precursor of anionic dye adsorption. The effect of flow rate, bed height and inlet concentration on the breakthrough curves were analyzed in terms of AFF adsorption performance. The experiment revealed that the increase in bed height and inlet concentration promoted the adsorption efficacy, whereas reduction was observed when the flow rate increased. The highest bed capacity obtained was 194.45 mg/g at adsorption condition of 5 ml/min flow rate, 100 mg/l inlet concentration and 50 mm of bed height. In order to determine the optimum operational parameters, the data were collected via the experiment fitted into Yoon and Nelson, and Thomas and Bed Depth Service Time (BDST) mathematical models. At various conditions, Thomas model closely defined the behaviors of the breakthrough curves. The maximum adsorption capacity calculated from Yoon–Nelson and Thomas models increased with the increase in flow rate and inlet concentration. However, a reduction was observed with the increase in bed height. Meanwhile, the BDST model exhibited good agreement with the experimental data as well as high correlation coefficient value r2 ~ 0.99, which indicated the validity of BSDT model for the column adsorption system with AFF. The experimental results attained had suggested that developed AFF is quite effective as a biosorbent for the removal of the dyes

Degradation of surfactants from domestic laundry effluent by electron beam irradiation

Surface active agent (surfactant) is the main ingredient in laundry detergent and other household cleaning agent. TWEEN20 is one of the nonionic surfactant which is widely used in detergent. Laundry effluent is one of the major contributor of domestic wastewater as laundering processes involves water-washing. Surfactant enters the environment when the effluents discharged into surface water and through sludge disposal on land. In order to protect the water bodies from any severe pollution, the effectiveness of high-energy ionizing radiation on decomposition of targeted surfactants, TWEEN20 from domestic laundry effluent at different operating condition were examined in this study. The experimental work was divided into two parts, part I verified the present of surfactants in laundry effluent using powdered and liquid detergents which will be collected from different sampling station. Whereas, part II involved the degradation of targeted pollutants by ionizing radiation technique. Two different type of laundry effluent was collected one using powdered detergent and another one using liquid detergent for fifteen days. Prior to irradiation, the characteristics of the water samples was analyzed in term of chemical oxygen demand (COD), total organic carbon (TOC), pH, and turbidity. Electron beam irradiation (EBI) was able to remove 100% of the TWEEN20 surfactant from laundry effluent for both liquid and powder detergent. The results obtained showed that electron beam irradiation is a very efficient and promising technology for the treatment of laundry effluent

A kinetic and mechanistic study of adsorptive removal of metal ions by imidazole-functionalized polymer graft banana fiber

Chemically modified fibrous bio-adsorbent extracted from banana trunk was synthesized for potential application in adsorption of heavy metal from wastewater. Glycidyl methacrylate (GMA) polymer graft was first introduced onto the fiber through electron beam irradiation technique. GMA-grafted fiber was subsequently functionalized with imidazole (IMI) group through epoxide ring-opening reaction where amine density of 2.00 mmol/g was achieved. The adsorbent was characterized with Scanning Electron Microscopy (SEM), Fourier Transformed Infrared Spectroscopy (ATR-FTIR), and Thermogravimetric Analyzer (TGA). An extensive kinetic and mechanistic study on the adsorptive removal of metal ions (Cu2+, Pb2+ and Zn2+) by IMI-functionalized GMA-grafted banana fiber is presented. The effects of pH and initial concentration on adsorption capacity were investigated. The adsorption data were correlated with pseudo-first and second order model and the isotherms were analyzed with Langmuir and Freundlich model in order to explain the kinetics and adsorption mechanisms of different metal ions. The thermodynamic studies revealed that the adsorption process for metal ions was exothermic. We also demonstrated that the IMI-GMA-grafted fiber can be regenerated using dilute HNO3 solution, and can be recycled up to 10 times while maintaining satisfactory adsorption performance. Lastly, the chemically modified bio-sorbent was used to treat a local domestic sewage water

Application of response surface modelling to economically maximize thorium (IV) adsorption

The fibrous adsorbent was synthesized by radiation-induced graft polymerisation with 2-(dimethylamino) ethyl methacrylate (DMAEMA). The fibrous grafted substrate with flexible side functional groups was used as an adsorbent to separate Th(IV) ions from an aqueous solution. The properties of the fibrous adsorbents were evaluated by attenuated total reflectance–Fourier-transform infrared spectroscopy, scanning electron microscopy, water uptake capacity and optical contact angle. The effects of adsorbent dosage, initial concentration, and reaction time on the adsorption capacity of the synthesized fibrous adsorbent were optimized using the Box–Behnken design of response surface methodology (RSM). The quadratic model showed an optimal adsorption capacity of 25.13 mg g–1 operating at an initial concentration of 5.5 mg L–1, reaction time of 24 h, and adsorbent dosage of 0.002 g at a maximum desirability value of 1. Under these adsorption conditions, the adsorption capacity of 24.87 mg g–1 was achieved from the experiment indicating good agreement with the predicted value. The applied optimisation procedure of incorporating RSM was effective in achieving the highest adsorption capacity using a minimum adsorbent dosage of only 0.002 g. The results indicate that the use of the fibrous adsorbent is economically promising for the separation of Th(IV) ions

Functionalized boron nitride composite ultrafiltration membrane for dye removal from aqueous solution

Two-dimensional (2D) hexagonal boron nitride (h-BN) nanosheets being isostructural to graphene, manifests robust properties for water treatment. However, it exhibits lower dispersibility in polar solvents limiting its utilization for membrane application. A facile two-step processes of (1) exfoliation of h-BN with urea followed by grafting polyethylene glycol using 3-Aminopropyl triethoxysilane to synthesize polyethylene glycol grafted boron nitride PEG-g-(NH2)BN and (2) deposition of as-fabricated nanosheets on the support membrane through vacuum filtration is carried. In the first step, the process leads to 6–14 layered amine-functionalized boron nitride BN(NH2) nanosheets of ~47 nm diameter and the later results of ~53 nm PEG-g-(NH2)BN nanosheets. In the second step, the deposition thickness was tuned through varying the concentration of the PEG-g-(NH2)BN nanosheet colloidal solution. The final functionalization imparts enhanced surface wettability through the transformation of superhydrophobic h-BN to superhydrophilic PEG-g-(NH2)BN. Improved wettability and porosity results in ultra-high water flux of 1253 L m−2 h−1 bar−1. Higher hydrodynamic resistance through the increasing thickness of deposited PEG-g-(NH2)BN nanosheets from approximately 3 μm–12 μm, results in permeance decrease from 1253 L m−2 h−1 bar−1 to 840 L m−2 h−1 bar−1 (about 33% decrement) and the MB exclusion improved to 98% removal even under different pH conditions. The exclusion properties of these membranes were tested stable with charge-neutral molecules

Selectivity of Copper by Amine-Based Ion Recognition Polymer Adsorbent with Different Aliphatic Amines

This paper investigates the selectivity of GMA-based-non-woven fabrics adsorbent towards copper ion (Cu) functionalized with several aliphatic amines. The aliphatic amines used in this study were ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA). The non-woven polyethylene/polypropylene fabrics (NWF) were grafted with glycidyl methacrylate (GMA) via pre-radiation grafting technique, followed by chemical functionalization with the aliphatic amine. To prepare the ion recognition polymer (IRP), the functionalized amine GMA-grafted-NWF sample was subjected to radiation crosslinking process along with the crosslinking agent, divinylbenzene (DVB), in the presence of Cu ion as a template in the matrix of the adsorbent. Functionalization with different aliphatic amine was carried out at different amine concentrations, grafting yield, reaction temperature, and reaction time to study the effect of different aliphatic amine onto amine density yield. At a concentration of 50% of amine and 50% of isopropanol, EDA, DETA, TETA, and TEPA had attained amine density around 5.12, 4.06, 3.04, and 2.56 mmol/g-ad, respectively. The amine density yield decreases further as the aliphatic amine chain grows longer. The experimental condition for amine functionalization process was fixed at 70% amine, 30% isopropanol, 60 °C for grafting temperature, and 2 h of grafting time for attaining 100% of grafting yield (Dg). The prepared adsorbents were characterized comprehensively in terms of structural and morphology with multiple analytical tools. An adsorptive removal and selectivity of Cu ion by the prepared adsorbent was investigated in a binary metal ion system. The IRP samples with a functional precursor of EDA, the smallest aliphatic amine had given the higher adsorption capacity and selectivity towards Cu ion. The selectivity of IRP samples reduces as the aliphatic amine chain grows longer, EDA to TEPA. However, IRP samples still exhibited remarkably higher selectivity in comparison to the amine immobilized GMA-g-NWF at similar adsorption experimental conditions. This observation indicates that IRP samples possess higher selectivity after incorporation of the ion recognition imprint technique via the radiation crosslinking process

Selectivity of Copper by Amine-Based Ion Recognition Polymer Adsorbent with Different Aliphatic Amines

This paper investigates the selectivity of GMA-based-non-woven fabrics adsorbent towards copper ion (Cu) functionalized with several aliphatic amines. The aliphatic amines used in this study were ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA). The non-woven polyethylene/polypropylene fabrics (NWF) were grafted with glycidyl methacrylate (GMA) via pre-radiation grafting technique, followed by chemical functionalization with the aliphatic amine. To prepare the ion recognition polymer (IRP), the functionalized amine GMA-grafted-NWF sample was subjected to radiation crosslinking process along with the crosslinking agent, divinylbenzene (DVB), in the presence of Cu ion as a template in the matrix of the adsorbent. Functionalization with different aliphatic amine was carried out at different amine concentrations, grafting yield, reaction temperature, and reaction time to study the effect of different aliphatic amine onto amine density yield. At a concentration of 50% of amine and 50% of isopropanol, EDA, DETA, TETA, and TEPA had attained amine density around 5.12, 4.06, 3.04, and 2.56 mmol/g-ad, respectively. The amine density yield decreases further as the aliphatic amine chain grows longer. The experimental condition for amine functionalization process was fixed at 70% amine, 30% isopropanol, 60 °C for grafting temperature, and 2 h of grafting time for attaining 100% of grafting yield (Dg). The prepared adsorbents were characterized comprehensively in terms of structural and morphology with multiple analytical tools. An adsorptive removal and selectivity of Cu ion by the prepared adsorbent was investigated in a binary metal ion system. The IRP samples with a functional precursor of EDA, the smallest aliphatic amine had given the higher adsorption capacity and selectivity towards Cu ion. The selectivity of IRP samples reduces as the aliphatic amine chain grows longer, EDA to TEPA. However, IRP samples still exhibited remarkably higher selectivity in comparison to the amine immobilized GMA-g-NWF at similar adsorption experimental conditions. This observation indicates that IRP samples possess higher selectivity after incorporation of the ion recognition imprint technique via the radiation crosslinking process

Radiation grafting of DMAEMA and DEAEMA‑based adsorbents for thorium adsorption

Radiation grafting of two tertiary amine methacrylates; 2-(dimethylamino)ethyl ethacrylate (DMAEMA) and 2-(diethylamino) ethyl methacrylate (DEAEMA) onto polyolefin non-woven fabric (PE/PP-NWF) was comparatively investigated in this study. In addition, the absorbent preparation process, grafting kinetics, and mechanism were investigated. The thermal properties were investigated by thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC). Fourier transform infrared (FTIR) spectroscopy was performed to confirm the successful grafting and incorporation of the two monomers functional groups onto PE/PP-NWF. X-ray diffraction (XRD) analysis was used to examine the differences between the crystal sizes and structures. Lastly, the adsorption of Th(IV) ion was investigated in batch mode. The results indicate that the radiation grafting of both DMAEMA and DEAEMA onto PE/PP-NWF required high activation energies with increasing temperatures from 313 to 333 K. Furthermore, P-DMAEMA and P-DEAEMA demonstrated different adsorption behaviors towards Th(IV). Results showed that P-DEAEMA exhibited lower Th(IV) adsorption capacity compared to P-DMAEMA, although both contain similar carbonyl and tertiary amino functional groups. These findings indicate that the molecular structure of the adsorbent was responsible. The molecular sizes increased with increasing branched carbon chains from the methyl to ethyl groups. Density functional theory (DFT) analysis indicated that induced steric effect eventually increases the inter-molecular repulsions caused by the additional CH2-groups in the structure, which reduces adsorption capacity