Sorption Of Naphthalene Research Articles

Sorption of three PAHs profile groups using eco-friendly and inexpensive hydroxyapatite extracted from camel bone

Hydroxyapatite (HAp) was used in the sorption study for three different polycyclic aromatic hydrocarbons (PAHs) ring structures (Naphthalene (NAP), Anthracene (ANT), and Chrysene). HAp powders were produced from Camelus bone as an eco-friendly and inexpensive source. Three distinct surface areas (66.56, 94.88, and 94.35 m2/g) at three different temperatures (500, 650, and 900 °C), were applied to prepare the HAp500, HAp650, and HAp900 samples after passing CO2 at 700 °C. It was obvious that the surface area of HAp was greatest at 650 °C as compared to 500 °C with a very small variation in uptake between HAP650 and HAP900. Furthermore, for ANT, HAp900 provides the best uptake. In addition, HAp650 is the best since calcining at 650 °C is less expensive than calcining at 900 °C. The effect of shaking time on the sorption of NAP, ANT, and CHR dissolved in n-hexane was carried out using HAp650. The impacts of sorbent amount, concentration, and temperature were studied. The study indicated that the uptake was 66.89, 69.49, and 19.67 mg/g after 120 min of equilibration. It was observed that the uptake of NAP, ANT, and CHR increased as the temperature increased up to 35 °C. A slight increase was obtained from 35–55 °C, indicating that the adsorption occurring on the HAp650 surface is endothermic. The positive values of Δ H demonstrated the endothermic nature of the adsorption process. Furthermore, the positive entropy of adsorption represents the adsorbent material’s affinity for NAP, ANT, and CHR. In addition, several isotherm models were used to deduce an adsorption mechanism. The adsorption system’s R2 values were 0.9615 for NAP, 0.8666 for ANT, and 1.00 for CHR. These values agree well with the Langmuir isotherm.

Polyaromatic hydrocarbon thin film layers on glass, dust, and polyurethane foam surfaces

An investigation was conducted into the dynamic behavior of two polyaromatic hydrocarbon (PAH) semi-volatile organic compound (SVOC) naphthalene (NAP) and benzo [ghi]perylene (BghiP) in air and on various surfaces including glass, dust, and polyurethane foam (PUF) to understand their interaction with different media. A confocal fluorescence microscope and an infrared microscope were employed to detect and monitor the concentration-, time-, and temperature-dependent changes of the aromatic NAP and BghiP species on the surfaces. Infrared two-dimensional mapping of the vibrational characteristic peaks was used to track the two PAHs on the surfaces. Gas chromatography-mass spectrometry (GC-MS) was employed to measure the gaseous concentrations. The sorption of NAP and BghiP on the surfaces was estimated using Arizona desert sand fine (ISO 12103-1 A2) dust and organic contaminant household (SRM 2585) dust. The surface-to-air partition coefficients of NAP and BghiP were estimated on the different surfaces of glass, dust, and PUF. Molecular dynamic simulations were performed on dust surfaces based on the Hatcher model to understand the behavior of NAP and BghiP on dust surfaces. The Weschler-Nazaroff model was introduced to predictPAH film accumulation on the surfaces, providing a better understanding of PAH interaction with different environmental media. These findings could contribute to developing effective strategies to mitigate the adverse impact of PAHs on the environment and human health.

Total organic carbon content as an index to estimate the sorption capacity of micro- and nano-plastics for hydrophobic organic contaminants

The worldwide existing micro- and nano-plastics (MNPs) showed high sorption capacity for hydrophobic organic contaminants (HOCs), and thus leading to change of the environmental behaviors and fates of HOCs. However, there is a lack of general index for evaluating the sorption capacity of MNPs for HOCs. Herein, we investigated the sorption of chlorobenzene, naphthalene and phenanthrene to 10 MNPs of different polymer types with and without UV-aging, respectively. It was found that the sorption was well fitted by Freundlich isotherm model with coefficients R2 in the range of 0.892–1.00, and aging of most MNPs resulted in decreased sorption capacity for naphthalene and phenanthrene but slightly increased sorption capacity for chlorobenzene. More importantly, for the 8 MNPs commonly present in the environment and with measured total organic carbon (TOC) covering the range of 23.0–91.9%, the logarithm sorption constant (logKd) values of the studied HOCs positively correlated with TOC contents of MNPs, with a good determination coefficient (R2) of 0.923 for naphthalene, 0.694 for chlorobenzene, and 0.565 for phenanthrene. Our study demonstrated that the TOC content of MNPs is a good index for estimating the contribution of total MNPs to the sorption of nonpolar HOCs in the environmental media.

Physicochemical Changes in Biomass Chars by Thermal Oxidation or Ambient Weathering and Their Impacts on Sorption of a Hydrophobic and a Cationic Compound.

This study examined conditions that mimic oxidative processes of biomass chars during formation and weathering in the environment. A maple char prepared at the single heat treatment temperature of 500 °C for 2 h was exposed to different thermal oxidation conditions or accelerated oxidative aging conditions prior to sorption of naphthalene or the dication paraquat. Strong chemical oxidation (SCO) was included for comparison. Thermal oxidation caused micropore reaming, with ambient oxidation and SCO much less so. All oxidative treatments incorporated O, acidity, and cation exchange capacity (CEC). Thermal incorporation of O was a function of headspace O2 concentration and reached a maximum at 350 °C due to the opposing process of burn-off. The CEC was linearly correlated with O/C, but the positive intercept together with nuclear magnetic resonance data signifies that, compared to O groups derived by anoxic pyrolysis, O acquired through oxidation by thermal or ambient routes contributes more to the CEC. Thermal oxidation increased the naphthalene sorption coefficient, the characteristic energy of sorption, and the uptake rate due to pore reaming. By contrast, ambient oxidation (and SCO) suppressed naphthalene sorption by creating a more hydrophilic surface. Paraquat sorption capacity was predicted by an equation that includes a CEC2 term due to bidentate interaction with pairs of charges, predominating over monodentate interaction, plus a term for the capacity of naphthalene as a reference representing nonspecific driving forces.

The influence of solid-phase organic carbon on the sorption of hydrophobic organic pollutants in landfill barriers, UK

The Oxford Clay from Bletchley, the Kimmeridge Clay from Kimmeridge Bay, Dorset, and Tertiary mud (Wittering Formation) from Whitecliff, Isle of Wight, United Kingdom were used as sorbent samples because of their distinctive organic material characteristics (Amorphous organic matter rich and/or phytoclast rich). Organic material was isolated for identification and analysis using a non-acid extraction method (heavy liquid) extraction and traditional methods involving HF digestion. These organic materials were then used to determine influences of extraction on hydrophobic organic contaminants, (toluene and naphthalene) sorption. Organic petrology classification was applied to identify the various types of isolated organic material. Amorphous organic matter from the Kimmeridge Clay displayed a higher sorption capacity (Sorption–desorption distribution coefficient (Kd), Kd = 6,481, 59, 670; for toluene and naphthalene, respectively) compared to literature values. Amorphous organic matter-rich sorbent extracts demonstrated a higher absorption capacity than the phytoclast-rich sorbents (e.g., Wittering Formation, Kd = 219, 10, 134; for toluene and naphthalene, respectively). Implications of results in landfill design/risk assessment and modelling are discussed.

Sorption and Desorption of the Model Aromatic Hydrocarbons Naphthalene and Benzene: Effects of Temperature and Soil Composition

Petroleum hydrocarbon (PHC) contamination is a global environmental issue. Understanding the key factors and mechanisms controlling the fate and mobility of PHCs in soils and aquifers is critical for environmental risk assessment, the development of remediation strategies, and policy decisions. This study focuses on the effects of soil composition and temperature on the sorption and desorption of two representative aromatic PHC compounds: benzene and naphthalene. The experiments were carried out using artificial sandy loam soil mixtures with temperatures ranging from 3 to 25℃. As expected, the sorption capacities of the soils were primarily controlled by the organic carbon (OC) content, while barely affected by the clay content. The sorption data for benzene and naphthalene followed linear to near-linear isotherms. Naphthalene sorption further increased with decreasing temperature, whereas temperature had little effect on benzene sorption. The latter was consistent with the very small magnitude of the sorption enthalpy of benzene. Under imposed dynamic temperature fluctuations, naphthalene sorption and desorption were shown to be reversible: model simulations demonstrated minimal kinetic limitation of the temperature-dependent soil-water partitioning. Our results imply that even in simple artificial soil systems, temperature variations can have complex, but predictable, effects on the soil-pore water partitioning of PHCs and, hence, on their mobility and bioavailability. Understanding the role of temperature is thus a prerequisite to unraveling the coupled abiotic and biotic processes that modulate the fate of PHCs in real-world soils.

Laccase-zein interactions at the air-water interface: Reactors on an air bubble and naphthalene removal from water

Zein and laccase were used to remove naphthalene from water using two approaches. The first approach sorbed naphthalene onto laccase-containing solid zein sorbents coagulated with either CaCl2 at pH = 13 or with Fe2Cl3 at pH = 10. These sorbents were never used before for this purpose. Fluorescence spectroscopy showed that laccase degraded naphthalene in water at neutral pH. Laccase activity was pH-dependent: laccase retained its activity after exposure to pH values as high as 10, and had maximum activity at pH = 5.5. Laccase immobilized in zein sorbents coagulated with Fe2Cl3 at pH = 10 had a relative activity of approximately 8%, whereas activity significantly decreased in zein sorbents coagulated with CaCl2 at pH = 13. Attenuated total reflection Fourier-Transform Infra-Red (ATR-FTIR) spectroscopy showed naphtalene sorption onto zein sorbents through hydrophobic interactions and CH/π bonding between naphthalene (the π base) and the aliphatic groups (hydrogen donors) of non-polar residues of zein. Gas Chromatography Mass Spectroscopy (GCMS) demonstrated naphthalene removal from water. The sorption capacity of zein sorbents was ≈ 14 mg/g at 21⁰C, and followed first-order kinetics with a rate constant of 0.0066 min−1. The second approach used zein and laccase to stabilize air bubbles in water, for air sparging applications. Air sparging injects air in contaminated aquifers to strip volatile contaminants from groundwater. Small, stable air bubbles with large surface area enhance contaminant removal. Previous studies used surfactants to stabilize air bubbles. However, they did not use foaming agents that were also able to adsorb and degrade contaminants. In this study, we produce “reactors on an air bubble” able to strip and degrade naphthalene in groundwater. Interfacial tension measurements showed that laccase and zein adsorbed at the air-water interface at either acidic or alkaline pH. At acidic pH, the compression isotherms of zein-laccase films at the air-water interface differed from those of the individual components, suggesting zein-laccase co-adsorption. At alkaline pH, iron promoted co-adsorption of zein-laccase at the air-water interface, likely by modulating their electrostatic interactions. Foams were stable at alkaline, with either zein alone or zein-laccase complexes, and iron enhanced foam stability. These results indicate that zein and laccase can facilitate the remediation of naphthalene by promoting air bubble stability and naphthalene sorption at the air-water interface, as well as its enzymatic degradation.

The effects of functional groups on the sorption of naphthalene on microplastics

Ubiquitous microplastics were recognized as an ideal carrier for polycyclic aromatic hydrocarbons (PAHs) to spread in nature or transfer to biota, thus posing risks to human health. However, little is known about how the functional groups in PAH derivatives influence their sorption onto microplastics as compared to parent PAHs. This study investigated the sorption of naphthalene (NAP) and its derivatives onto polystyrene microspheres with (MP-COOH) or without (MP) surface modification of the carboxyl group. NAP derivatives with charged groups (e.g., –NH2, –OH and –COOH) reached the sorption equilibrium more early than NAP and its derivative with an uncharged group (e.g., –CH3), whereas their sorption capacities (Kd = 6.0–8.4 L/g for MP, Kd = 4.5–6.3 L/g for MP-COOH) were significantly lower than that of the latter (Kd = 11.6–12.0 L/g for MP, Kd = 9.4–10.0 L/g for MP-COOH). The inhibition of charged groups on sorption could be attributed to their facilitation on molecular polarity and, thus, their lower hydrophobicity (LogKOW) since hydrophobicity was the crucial factor controlling the sorption of NAP and NAP derivatives onto both MP and MP-COOH. Computational modeling further showed that charged functional groups would weaken the π-π interaction or strengthen the repulsion between NAP or NAP derivative molecule and MP or MP-COOH molecule, which might also contribute to the suppressed sorption. This study provides new insight into the affinity of PAH derivatives with microplastics, which, therefore, improves our understanding of the environmental fates of microplastics and the organic pollutants.

Sorption of naphthalene and 2-naphthol onto porous carbonaceous materials as a function of pore size, metals, and oxygen-containing groups.

The important role of oxygen-containing groups of porous carbonaceous materials (PCMs) on sorption of organic compounds has been realized, but whether these groups can generate different joint effects, especially when oxidized PCMs with different pore sizes are complexed with heavy metals (Cu2+), remains ambiguous. The present study aimed to determine how pore sizes, metal ions, and oxygen-containing groups as a function affect the sorption of naphthalene and 2-naphthol to PCMs (e.g., activated carbons/ACs and mesoporous carbon/CMK-3). The H2-reduced oxidized PCMs were used as the control of low oxygen content to avoid changes in the pore structure properties compared with the oxidized PCMs. Oxygen-containing groups considerably decreased the sorption of naphthalene and 2-naphthol to PCMs because of their weaker hydrophobic interaction and fewer sorption sites. Notably, naphthalene sorption on oxidized AC was inhibited with Cu2+ because of the steric constraint of Cu2+ hydration shells of the micropores. However, pore blockage by Cu2+ reduced the mesopore size of oxidized CMK-3, leading to enhanced pore filling effect and cation-π bonding, and therefore increased naphthalene sorption. For 2-naphthol, the sorption to oxidized PCMs initially increased and then decreased with increasing Cu2+ concentration attributed to the fewer Cu2+ acting as a bridging agent and excess Cu2+ competing for sorption sites.

Naphthalene Removal with Layered Double Hydroxides

Naphthalene is a hazardous pollutant. It has a negative impact on human health and environment. Its manufacturing process is accompanied by gaseous naphthalene emissions into the air of the premises and then into the atmosphere, thus polluting the environment. There is currently no existing method to remove naphthalene from the gas phase which is capable of meeting the required environmental standards. The goal of this research was to investigate the mechanism of naphthalene removal from the gas phase by the sorption method using Mg/(Al+Mg) layered double hydroxides (LDHs) and to develop naphthalene removal technology to meet the required environmental standards. The methods for obtaining selective sorbents of naphthalene and its derivatives have been investigated. The technology of naphthalene removal from gas phase using Mg/(Al+Mg) LDHs has been developed. The technological parameters of reactors have been calculated. The final concentration of naphthalene of 12 mg/m3 was obtained which appeared to be lower than the maximum allowed concentration. The efficiency of naphthalene sorption with LDHs was found to be over 95%.

Preparation and characterization of a recyclable high-branched/genera- tion dendrimer nano-polymer based on the enhanced magnetic core for naphthalene sorption from aqueous solutions

Preparation and characterization of a recyclable high-branched/genera- tion dendrimer nano-polymer based on the enhanced magnetic core for naphthalene sorption from aqueous solutions

Adsorption site-dependent transport of diclofenac in water saturated minerals and reference soils

Use of reclaimed water for irrigation is a main way for pharmaceutical compounds such as diclofenac getting into the soil environment. However, the role of minerals, especially iron oxides, in the diclofenac adsorption to soils with low soil organic matter (SOM) is still in the lack of evaluation. In this study, adsorption of diclofenac onto six minerals (five nature minerals-hematite, goethite, magnetite, kaolinite and aluminium oxide and one engineered mineral-activated aluminia) and five reference soils was investigated by column chromatography. Adsorption of diclofenac onto minerals and soils was totally reversible and interactions such as H-bonding were the primary mechanisms. Adsorption affinity of iron oxides was much higher than that of nature silicon and aluminum oxides. Diclofenac tended to be adsorbed by mineral surface -OH groups with high thermodynamic stability, which were dehydroxylated at high temperature. Compared with the SOM-dominated sorption of naphthalene, adsorption of diclofenac onto soils was controlled by bonding with surface -OH groups of iron oxides. Adsorption coefficients of diclofenac onto soils can be well predicted by contents of extracted Fe by diethylenetriamine pentaacetic acid (DTPA) instead of total iron oxides contents, suggesting that the bonding was adsorption site-dependent. These findings highlighted the importance of iron oxides in the adsorption of diclofenac (an anionic pharmaceutical compound) in soils with relatively low SOM (e.g., 1.03-3.45%). It also indicated that contents of effective surface -OH groups and DTPA-Fe were the promising parameters to develop the predictive models for diclofenac adsorption onto minerals and soils, respectively.

Sorption of benzene and naphthalene on (semi)-arid coastal soil as a function of salinity and temperature

Considerable activities from the oil and natural gas sector have risen some concerns about the pollution of soil and groundwater by petroleum hydrocarbons (PHCs) in (semi)-arid coastal regions. The understanding of the fate and transport of PHCs in these regions is therefore necessary to develop strategies for remediation. To quantify the sorption rates of PHCs in (semi)-arid coastal soil environments, we conducted a series of controlled-laboratory batch experiments under variable temperature and salinity conditions. The soil samples were collected from the eastern coast of Qatar which is near the two largest off-shore oil and natural gas fields of the country (North Gas and Al-Shaheen Oil Fields), and the volatile benzene and naphthalene were used as PHCs. The characterization of soil samples showed sand classification with the texture class of sabkha and saline beach sandy soils with calcite as potential dominant mineral. The concentrations of dissolved chloride and sodium were found to be high (> 400 mg L−1) with a chloride-to‑sodium ratio of about 1.7. The results of sorption experiments showed that the rates of naphthalene sorption were more than for benzene, where the initial aqueous concentrations of benzene and naphthalene were reduced at equilibrium due to sorption by about 14–25% and 65–79%, respectively. This difference was attributed mainly to the organic carbon-water partitioning coefficient which is higher for naphthalene. The sorption rate experiments showed that sorption was stronger for benzene under higher salinity and lower temperature conditions. The sorption of naphthalene was not affected by the change in salinity but increased by 18% when the temperature decreased from 35 to 5 °C. A sorption kinetic model was also applied to define the sorption behavior of benzene and naphthalene for the coastal soil collected in Qatar and the best fits were achieved with the Langmuir sorption isotherm.

Soils impacted by PAHs: Would the stabilized organic matter be a green tool for the immobilization of these noxious compounds?

ABSTRACTThe objective of this study was to investigate the role of stabilized organic matter (vermicompost) and tropical soils in the sorption of naphthalene, anthracene and benzo[a]pyrene. The results obtained for the three compounds were extrapolated for the priority polycyclic aromatic hydrocarbons (PAHs) pollutants according to Environmental Protection Agency (US EPA). To evaluate the sorption process, high performance liquid chromatography was employed and the data was fitted by Freundlich isotherms. The results suggest that the sorption effect generally increases with the number of benzene rings of the PAHs, and that the persistence of PAHs in the environment is possibly related to the number of benzene rings in the PAH molecule. In addition, the pH of the vermicompost can strongly affect the adsorption process in this matrix.

Sorption of ionic and nonionic organic solutes onto giant Miscanthus-derived biochar from methanol-water mixtures

The sorption of naphthalene (NAP) and 1-naphthoic acid (1-NAPA) onto giant Miscanthus–derived biochar was investigated in methanol volume fractions (fc) of 0–0.6 as a function of ionic composition (5mM CaCl2 and 10mM KCl) and liquid pH (2 and 7). The sorption onto biochar was nonlinear with 0.42≤N≤0.95; thus, a concentration-specific sorption constant (Km) was compared. The Km log linearly decreased with increasing fc, except for 1-NAPA from a CaCl2 mixture at pH7. Isotherm data was fitted with a cosolvency sorption model through which the slope (ασ) of the inverse log linear Km-fc plot and empirical constant (α) were obtained. NAP sorption was well described by the cosolvency model with the α value being 0.41–0.53, indicating a methanol–biochar interaction favoring more sorption than the cosolvency based prediction. In particular, the slope (ασ) of 1-NAPA was lower than that of NAP, indicating less reduction of 1-NAPA sorption (i.e., lower α value) by methanol. In comparison with other sorbents, the α value was approximately intermediate between a humic substance and kaolinite clay. An analysis of FT-IR spectra suggested the transformation of O-containing functional groups by methanol, which will subsequently boost the π–π interaction between an organic solute and biochar. Moreover, Ca2+-induced sorption between anionic 1-NAPA and a negatively charged biochar surface was also fortified in the methanol mixture. The results revealed unexplored cosolvent effects on organic solute sorption onto biochar and identified the hydrophobic and hydrophilic sorption moieties of biochar as affected by the cosolvent.

Effects of humic acid and heavy metals on the sorption of polar and apolar organic pollutants onto biochars

The effects of humic acid (HA) and heavy metals (Cu2+ and Ag+) on the sorption of polar and apolar organic pollutants onto biochars that were produced at temperatures of 200 °C (BC200) and 700 °C (BC700) were studied. Due to the plentiful polar functional groups on BC200, cationic propranolol exhibited higher levels of sorption than naphthalene on BC200 while naphthalene and propranolol showed similar sorption capacities on BC700. HA changed the characteristics of biochars and generally inhibited the sorption of target organic pollutants on biochars; however, enhancement occurred in some cases depending on the pollutants involved and their concentrations, biochars used and the addition sequences and concentrations of HA. On BC200, HA modifications mainly influenced sorption by decreasing its polarity and increasing its aromaticity, while on BC700, the surface area and pore volume greatly decreased due to the pore-blocking effects of HA. Residue dissolved HA in solution may also contribute to sorption inhibition. Complexation between polar functional groups on BC200 and heavy metals slightly enhanced the sorption of neutral naphthalene and significantly enhanced that of anionic 4-nitro-1-naphtol, while limited the sorption of cationic propranolol. Heavy metals together with their associated water molecules decreased the sorption of target chemicals on BC700 via pore-filling or pore-mouth-covering. Inhibition of heavy metals for 4-nitro-1-naphthol was found to be the weakest due to the bridge effects of heavy metals between 4-nitro-1-naphtol and BC700. The higher polarizability of Ag+ led to the increase of its sorption on biochars in the presence of organic aromatic pollutants. The results of the present study shed light on the sorption mechanisms of bi-solute systems and enable us to select suitable biochar sorbents when chemicals co-exist.

Effect of naphthalene on transport and retention of biochar colloids through saturated porous media

In this study, we conducted batch and column experiments to study the effect of naphthalene on retention and transport of biochar colloids in saturated porous media under different solution chemistry. The results of the batch adsorption experiments showed that the ionic strength and pH had negligible effect on naphthalene sorption onto biochar colloids. The results from the column experiments presented that biochar colloid transport decreased with increasing naphthalene concentrations, the presence of naphthalene in suspensions reduced the mobility of biochar colloids in porous media under various ionic strength and pH conditions. The reason was that nonpolar naphthalene was strongly attached on biochar colloid surface, and further lowered the zeta potential of biochar colloids due to charge-shielding. The findings from this study have important implications for biochar application in naphthalene contaminated soils.

Highly efficient capture of naphthalene by nonionic surfactants in hydrogel capsules

The impregnation of Triton X-100 (TX100) in chitosan capsules (TCC) via an anionic surfactant gelation method was investigated for the sorption of naphthalene (NAP) from aqueous solutions. Impregnation with TX100 enhanced NAP sorption at all tested concentrations of TX100, ranging from 0.1 to 10g/l. The highest NAP sorption capacity (68.7mg/g) was obtained at 2g/l of TX100, a capacity 5.1-fold higher than that of chitosan capsules without TX100 impregnation (CC) (13.4mg/g). The highest molar sorption ratio of capsule (MSRC) was 12.23mol NAP/mol TX100 at 0.1g/l, which was much higher than the MSRB for beads (0.70) and the MSRW for the aqueous phase (0.11). Thus, when a nonionic surfactant is present in a hydrogel capsule, the ability of the surfactant to solubilize organic chemicals can be significantly increased compared to the surfactant in water or in hydrogel beads.

Sorption of naphthalene and its hydroxyl substitutes onto biochars in single-solute and bi-solute systems with propranolol as the co-solute

The sorption of naphthalene and its hydroxyl-substituted compounds onto two biochars that were produced at different temperatures was studied. The influences of propranolol as a co-solute and solution pH on the sorption were investigated. The sorption capacities of 1-naphthol and 4-nitro-1-naphthol on the biochar with a pyrolytic temperature of 200°C (BC200) were greater compared to naphthalene. This occurred because the substitution of hydroxyl- and nitro-groups on the aromatic ring enhanced surface adsorption, e.g. hydrogen bond and π-π electron donor-acceptor interaction, while the hydroxyl in 1-naphthalenemethanol did not show the promoting effect. The sorption on the biochar with a pyrolytic temperature of 700°C (BC700) followed a different sequence of 4-nitro-1-naphthol<1-naphthalenemethanol<1-naphthol<naphthalene, which was determined by the hydrophobicity and molecular volume of the sorbates, indicating the dominance of hydrophobic partition and pore-filling in the adsorption on BC700. The co-existence of propranolol promoted the surface hydrophobicity of BC200, which led to an enhancement in the sorption of naphthalene and 1-naphthalenemethanol. Propranolol prohibited the sorption of 1-naphthol by competing for the mutual available surface adsorption sites. The ion-pair reaction between anionic 4-nitro-1-naphthol and cationic propranolol increased the sorption of 4-nitro-1-naphthol. On BC700, propranolol generally prohibited the sorption of the tested sorbates mainly due to competition and pore-blocking. The influence of pH was complicated in both single-solute and bi-solute systems. It simultaneously affected the surface charge of biochars and the form of the tested compounds, which led to the shifting of sorption mechanisms. The finding will shed light on the suitable application of biochar technology.

Naphthalene sorption on red clay and halloysite modified by quaternary ammonium salts

Sorption of naphthalene on modified red clay and halloysite was carried out successfully. It was established that the process was of pseudo-second-order mechanism. The maximum sorption capacities w...