The sorption of two phthalate esters (PAEs) and phenanthrene (PHE) by different natural organic matter fractions (NOMs) was examined. The surface area of the NOMs correlated positively with the starting decomposition temperature (SDT), implying increased number of micropores with the rise of condensation. Sorption of PHE on nonhydrolyzable carbons (NHCs) and other NOMs was respectively dependent on aromatic and aliphatic C contents. Likely physical blocking of the aliphatic moieties and input of black carbon materials led to elevated sorption capacity for PHE of aromatic domains in the NHCs. Sorption of PAEs by NOMs excluding NHCs was jointly regulated by hydrophobic partitioning and H-bonding interactions. The SDT of the NOMs correlated negatively with the Koc when SDT ≥304 °C, likely because the highly condensed domains may impair the availability of amorphous moieties for sorption. This study highlights the influence of domain accessibility of NOMs on sorption of hydrophobic organic contaminants.

Microplastics are ubiquitous in the marine environment but characterizing them in marine organisms is challenging. Herein we describe a method to detect, identify, and quantify microplastics in marine mussels (Mytilus edulis) using thermal gravimetric analysis – Fourier Transform infrared spectroscopy – gas chromatography mass spectrometry (TGA-FTIR-GC/MS) after extracting and isolating the microplastics using chemical digestion, density separation, and filtration. Combining the three instrumental techniques adds discriminatory power as temperature profiles, chromatograms, and vibrational and mass spectra differ among common plastics. First, we tested several digestion schemes after spiking the mussels with plastics commonly found in the marine environment, including polyethylene (PE), polystyrene (PS), polypropylene (PP) and polyvinyl chloride (PVC). KOH (10%, w/v) was the most suitable reagent, providing good recoveries (>97%) without degrading the microplastics. We show that the technique TGA-FTIR-GC/MS can be optimized to readily determine both the type (polymer) and amount (mass) of microplastics in the sample. Applied to 100 mussels from each of six locations along the coast of China, we found an average of 0.58 mg of plastic per kg of tissue (range 0.16–1.71 mg/kg), with PE being the most abundant type of plastic measured. Among the coastal cities, mussels from Dalian had the highest microplastic content. Overall, we demonstrate that the method is a powerful technique to quantify masses of microplastics in marine mussels, a species commonly used as a bioindicator of pollution, and may be applied to other biota as well.

The perdurability of plastics in the environment is one of the major concerns of plastic pollution and, as a consequence, oceans are accumulating large amounts of plastic. The degradation of conventional and biobased materials was evaluated through a laboratory experiment for a year simulating four different conditions in the marine environment. The water column environmental compartment was simulated under euphotic and aphotic (with and without light availability) conditions. The seafloor environmental compartment was simulated with sediment under non-polluted and polluted conditions. By combining weight loss (%), spectroscopic and thermal analyses, the degradation patterns regarding the polymer structure were assessed. The studied biobased materials were polylactic acid (PLA) based materials and showed higher degradability than conventional ones. The weight loss of conventional materials was not influenced by the water column or sediment, while in PLA-based materials, the degradation rates were ca. 5 times greater in the sediment than in the water column. The absorbance (Abs) value at 3400 cm⁻¹ for polyethylene terephthalate (PET), and carbonyl (CO) index for PET and PLA could be useful to detect early signs of degradation. The crystallization index could be a useful parameter to discriminate degradation stages. The obtained results highlight the different degradability rates of materials depending on the specific environmental marine conditions.

The sorption of PAH on 12 different sediments was investigated and was correlated to their corresponding organic matter (OM) content and quality. For this purpose, the OM was precisely characterized using thermal analysis consisting in the successive combustion and quantification of the increasingly thermostable fractions of the OM. Simultaneously, the water-exchangeable fraction of the sorbed PAH defined as the amount of PAH freely exchanged between the water and the sediment (by opposition to the PAH harshly sorbed to the sediments particles) was determined using a passive sampler methodology recently developed. The water concentrations, when the sediment-water system is equilibrated, were also assessed which allows the determination of the sediment-water distribution coefficients without artifacts introduced by the non water-exchangeable fraction of PAH. Hence, the present study provides the distribution coefficients of PAH between the water and 4 different OM fractions combusted at a specific temperature range. The calculated distribution coefficients demonstrate that the sedimentary OM combusted at the intermediate temperature range (between 300 °C and 450 °C) drives the reversible sorption of PAH while the inferred sorption to the OM combusted at a lower and higher temperature range does not dominate the partitioning process.

As a global pollutant, microplastics have attracted attention from the public and researchers. However, the lack of standard and time-saving methods for analysis has become one of the bottlenecks in microplastics research. Here, we demonstrate TGA coupled to FTIR to identify and quantify certain microplastics in environment. Samples were pyrolyzed in TGA and the pyrolysis gases were analyzed by FTIR. Combining TGA and FTIR data adds discriminatory power as temperature profiles and absorption spectra differ among several common plastics. To quantify on a mass basis, we calibrated on characteristic IR peaks at temperatures of maximum weight loss for individual polymers. The method can distinguish PVC, PS and was validated by spiking samples with known quantities of microplastics. The result of field sample experiments showed that TGA-FTIR can be used to identify and quantify PVC and PS in bivalves, seawater and soil. And the method may be applicable to environmental samples.

In this study, a chabazite-rich tuff (CHA) from the Bala deposit of Ankara region (Turkey) and its modified forms (CuCHA, AgCHA, FeCHA, and HCHA samples) were investigated at 273 and 298 K using volumetric apparatus up to 100 kPa. The chabazite samples were characterized by using thermal analysis (TG-DTG-DTA), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with detector X-ray energy dispersive (SEM-EDX), Fourier transform infrared (FT-IR), and N₂ adsorption methods. It was found that natural chabazite is composed of predominantly chabazite with small amounts of clinoptilolite and erionite. XRD showed that there are major structural changes to Fe- and H-exchanged chabazite samples. Capacity of chabazites for CH₄ ranged from 0.168 and 1.341 mmol/g. Among all the modified forms, it was observed that Ag form of chabazite zeolite had the greatest methane adsorption capacity at both temperatures.

The effect of styrene-divinylbenzene copolymer functionalization by carboxylic acid groups on the adsorption of p-nitrophenol (p-NP) from aqueous solutions was investigated. The adsorption capacity of p-NP onto the functionalized copolymer (CP-F) was compared with that of the precursor copolymer, the chloromethylated styrene-divinylbenzene copolymer (CP-N). The two copolymers were characterized by Fourier transform infrared (FTIR) spectroscopy, thermal analysis (DSC-TG), specific surface area and particle size measurements, pore size distribution, scanning electron microscopy (SEM), and elemental analysis (EDX). The adsorption of p-NP was substantially enhanced after the polymer functionalization, and it was demonstrated that hydrogen bonding is principally responsible for the high adsorption capacity of CP-F in comparison with CP-N. The adsorption kinetics of p-NP adsorption onto CP-F was well described by the pseudo-second-order model. From the four investigated isotherms, Langmuir, Freundlich, Redlich-Peterson, and Sips, the equilibrium data were better described by the Sips model. The maximum adsorption capacity of the CP-F polymer resulting from the Sips isotherm was 243.37 mg g⁻¹. The capacity of regeneration and reuse of the CP-F polymer was evaluated in three consecutive cycles of adsorption-desorption.

Fibrous mats of polymer/clay were obtained by electrospinning method, and their capacity for heavy metals removal from water was evaluated. Four different fibrous mats were prepared from a corresponding polymer/clay solutions. The precursor materials employed were poly-ε-caprolactone, polyvinyl alcohol polymers, kaolin, and metakaolin clays. Raw materials and the prepared fiber mats characterization were carried out using scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, termogravimetric analysis, differential thermal analysis, and differential scanning calorimetry. Elemental composition of the materials was obtained using energy-dispersive X-ray spectroscopy. The environmental applications of polymer/clay materials were tested for water treatment by heavy metals (cadmium (Cd⁺²), chromium (Cr⁺³), copper (Cu⁺²), and lead (Pb⁺²)) sorption. Kinetic adsorption studies were conducted employing heavy metal solutions with initial concentration of 200 mg/L, and the amount of heavy metal adsorbed and kinetics parameters was determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES). According to the kinetic data, the adsorption process of Cd⁺², Cr⁺³, Cu⁺², and Pb⁺² onto polymer/clay is favorable for the prepared materials and they follow a pseudo-first-order model according to the kinetic analysis. Additionally, the intraparticle diffusion was evaluated by applying the Morris and Weber model; in order to investigate the contribution of film resistance to the kinetics of the heavy metals adsorption, the adsorption kinetic data was further analyzed by Boyd’s film-diffusion model.

Black rice husk ash (BRHA) was obtained by means of thermal degradation of raw rice husks (RRH) on a pilot plant fluidized bed reactor. BRHA was characterized using chemical analyses, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and thermal analysis. The kinetics was studied using batch adsorption technique and on the basis of prior characterization by X-ray diffraction patterns and scanning electron microscopy. The adsorption capacities of diesel fuel at 288, 293 and 298 K onto BRHA were determined. Results showed that the material studied has very high adsorption capacity and low cost and may successfully be used as an effective adsorbent to clean up spills of oil products in water basins. The adsorption of diesel fuel onto BRHA proceeds rapidly to reach adsorption equilibrium in about 10 min. The saturated BRHA can be burnt in incinerators, industrial ovens or steam generators, and through this way ecological and economic benefits are attained.

In this study, p-tert-butylcalix[4]-aza-crown (CAC) immobilized sporopollenin (Sp) was used as a sorbent for the removal of Cu(II), Pb(II) and Zn(II) from aqueous media. Sporopollenin was firstly functionalized with 3-chloropropyltrimethoxysilane (CPTS) in order to obtain chloro-sporopollenin (Sp-Cl). The Sp-Cl was reacted subsequently with CAC yielding CAC-bonded sporopollenin (Sp-Cl-CAC). The new sorbent was characterized by infrared spectroscopy (FTIR), thermal analysis (TG/DTG) and scanning electron microscopy (SEM). The sorption properties of modified sorbent (Sp-Cl-CAC) are also investigated. The optimum pH values for the separation of metal ions from aqueous solution onto Sp-Cl-CAC were 5.0 for Pb(II) and Cu(II) and 5.5 for Zn(II). The maximum sorption capacities for Cu(II), Pb(II) and Zn(II) were 0.07 (4.44 mg g), 0.07 (4.58 mg g) and 0.14 (29.00 mg g) mmol g, respectively. Sorption thermodynamic parameters of such as free energy ( ∆G), enthalpy ( ∆H), and entropy ( ∆S) were evaluated.