Application of machine learning in river water quality management: a review.

Machine learning (ML), a branch of artificial intelligence (AI), has been increasingly used in environmental engineering due to the ability to analyze complex nonlinear problems (such as ones connected with water quality management) through a data-driven approach. This study provides an overview of different ML algorithms applied for monitoring and predicting river water quality. Different parameters could be monitored or predicted, such as dissolved oxygen (DO), biological and chemical oxygen demand (BOD and COD), turbidity levels, the concentration of different ions (such as Mg2+ and Ca2+), heavy metal or other pollutant's concentration, pH, temperature, and many more. Although many algorithms have been investigated for the prediction of river water quality, there are several which are most commonly used in engineering practice. These models mostly include so-called supervised learning algorithms, such as artificial neural network (ANN), support vector machine (SVM), random forest (RF), decision tree (DT), and deep learning (DL). To further enhance prediction power, novel hybrid algorithms, could be used. However, the quality of prediction is not only dependent on the applied algorithm but also on the availability of previously mentioned water quality parameters, their selection, and the combination of input data used to train the ML model.

Long-term air pollution and road traffic noise exposure and COPD: the Danish Nurse Cohort.

BACKGROUND: While air pollution has been linked to the development of chronic obstructive pulmonary disease (COPD), evidence on the role of environmental noise is just emerging. We examined the associations of long-term exposure to air pollution and road traffic noise with COPD incidence. METHODS: We defined COPD incidence for 24 538 female nurses from the Danish Nurse Cohort (age >44 years) as the first hospital contact between baseline (1993 or 1999) and 2015. We estimated residential annual mean concentrations of particulate matter with an aerodynamic diameter <2.5 µm (PM2.5) since 1990 and nitrogen dioxide (NO2) since 1970 using the Danish Eulerian Hemispheric Model/Urban Background Model/Air Geographic Information System modelling system, and road traffic noise (Lden) since 1970 using the Nord2000 model. Time-varying Cox regression models were applied to assess the associations of air pollution and road traffic noise with COPD incidence. RESULTS: 977 nurses developed COPD during a mean of 18.6 years' follow-up. We observed associations with COPD for all three exposures with HRs and 95% CIs of 1.19 (1.01-1.41) per 6.26 µg·m-3 for PM2.5, 1.13 (1.05-1.20) per 8.19 µg·m-3 for NO2 and 1.15 (1.06-1.25) per 10 dB for Lden. Associations with NO2 and Lden attenuated slightly after mutual adjustment, but were robust to adjustment for PM2.5. Associations with PM2.5 were attenuated to null after adjustment for either NO2 or Lden. No potential interaction effect was observed between air pollutants and noise. CONCLUSION: Long-term exposure to air pollution, especially traffic-related NO2, and to road traffic noise were independently associated with COPD.

Biochar application in organics and ultra-violet quenching substances removal from sludge dewatering leachate for algae production.

Algae production in nutrient rich sludge dewatering leachate after biogas production is a promising option for wastewater treatment plants. However, the ultra-violet (UV) absorbing characteristic of UV-quenching substances (UVQS) existing in these waters can notably reduce the light transmission within the liquid body. The present work demonstrates a comparative adsorptive removal of UVQS, and other organic substances (expressed as COD and TOC) onto the "acid catalyst" functionalised adsorbent (PPhA) and commercial activated carbon (CAC) from leachate originating from leftover sludge dewatering after biogas production. Laboratory scale column studies were performed to investigate the adsorption performance of selected parameters. The PPhA increased the UV transmittance of leachate more than 4 times and outperformed CAC. Bed Depth Service Time and Yan models were used on the experimental data in order to estimate the maximum adsorption capacity and evaluate the characteristics of the fixed-bed. The PPhA equilibrium uptake of COD and TOC amounted to 5.7 mg/g and 0.9 mg/g, respectively. The postulated removal mechanism in environmentally relevant conditions (e.g., pH neutral) suggested a complex interaction between the biochar and organic macromolecules. Diluted phosphoric acid solution (0.01 mol/L) was successfully used for the column regeneration. Beside the UVQS, PPhA showed affinity towards toxic heavy metals (e.g., Pb, Ni, Co) pointing out the rich surface chemistry of the PPhA. Based on the obtained results and successfully implemented scale-up methodology, the low-cost PPhA adsorbent might effectively compete with the CAC as a highly efficient platform in wastewaters leachate processing.

Occurrence of aflatoxin M1 in human milk samples in Vojvodina, Serbia: Estimation of average daily intake by babies.

The objectives of the study were to determine the aflatoxin M1 content in human milk samples in Vojvodina, Serbia, and to assess the risk of infants' exposure to aflatoxins food contamination. The growth of Aspergillus flavus and production of aflatoxin B1 in corn samples resulted in higher concentrations of AFM1 in milk and dairy products in 2013, indicating higher concentrations of AFM1 in human milk samples in 2013 and 2014 in Serbia. A total number of 60 samples of human milk (colostrum and breast milk collected 4-8 months after delivery) were analyzed for the presence of AFM1 using the Enzyme Linked Immunosorbent Assay method. The estimated daily intake of AFM1 through breastfeeding was calculated for the colostrum samples using an average intake of 60 mL/kg body weight (b.w.)/day on the third day of lactation. All breast milk collected 4-8 months after delivery and 36.4% of colostrum samples were contaminated with AFM1. The greatest percentage of contaminated colostrum (85%) and all samples of breast milk collected 4-8 months after delivery had AFM1 concentration above maximum allowable concentration according to the Regulation on health safety of dietetic products. The mean daily intake of AFM1 in colostrum was 2.65 ng/kg bw/day. Results of our study indicate the high risk of infants' exposure, who are at the early stage of development and vulnerable to toxic contaminants.

Evaluation of the adsorption potential of eco-friendly activated carbon prepared from cherry kernels for the removal of Pb2+, Cd2+ and Ni2+ from aqueous wastes.

Development, characterization and evaluation of the efficiency of cost-effective medium for the removal of Pb2+, Cd2+ and Ni2+ from aqueous systems, as a novel, eco-friendly solution for wastewater remediation were done. The precursors for low-cost adsorbent were lignocellulosic raw materials (sweet/sour cherry kernels), as industrial byproducts and components of organic solid waste. Activated carbon synthesis was carried out by thermochemical conversion (H3PO4, 500 °C) in the complete absence of inert atmosphere. Characterization of the activated carbon was performed by elemental analysis, FTIR, SEM, EDX and BET. BET surface area corresponds to 657.1 m2 g-1. The evaluation also included the influence of pH, contact time, solute concentration and adsorbent dose on the separation efficiency in the batch operational mode. The equilibrium and kinetic studies of adsorption were done. The maximum adsorption capacity of the activated carbon for Cd2+ ions was calculated from the Langmuir isotherm and found to be 198.7 mg g-1. Adsorption of Pb2+ and Ni2+ were better suitable to Freundlich model with the maximum adsorption capacity of 180.3 mg g-1 and 76.27 mg g-1, respectively. The results indicate that the pseudo-second-order model best describes adsorption kinetic data. Based on desorption study results, activated carbon was successfully regenerated with HNO3 for 3 cycles. In order to provide the results for basic cost-effective analysis, competing ion-effects in a real sample have been evaluated.

Meat industry wastewater: microbiological quality and antimicrobial susceptibility of E. coli and Salmonella sp. isolates, case study in Vojvodina, Serbia.

Wastewater from meat processing industries is a fusion of compounds with a high load of organic matter, and pathogen microorganisms like Escherichia coli, and Salmonella sp. The aim of this research was to determine microbiological characteristics of the wastewater discharged from the meat processing industry in order to get a more detailed insight into meat industry wastewater pollution, and to evaluate the resistance of bacterial strains E. coli and Salmonella sp. to antibiotics. The evaluation of the antimicrobial susceptibility was performed on 37 strains of E. coli and eight strains of Salmonella sp. to nine different antibiotics. The number of faecal pollution indicators was very high in all samples. From a total of 37 strains of E. coli, a moderate degree of resistance was shown to tetracycline (37.83%); a low degree of resistance to ampicillin (21.62%), streptomycin (24.32%), trimethoprim-sulfamethoxazol (18.92%) and nalidixic acid (16.22%); and very low to: chloramphenicol (13.51%), ciprofloxacin (2.7%), gentamicin and cefotaxime (0.0%). The results for eight strains of Salmonella sp. show that all eight isolates had some degree of susceptibility to nine tested antimicrobial agents and six strains were fully susceptible to all tested antibiotics.

Comparison of two carbonaceous supported Fe-rich adsorbents for arsenate removal: A functionalisation and mechanistic study with applicability to groundwater treatment.

The presence of arsenic in groundwater, and through this in drinking water, has been shown to present a serious risk to public health in many regions of the world. In this study, two iron-rich carbonous adsorbents were compared for the removal of arsenate (As(V)) from groundwater. Biochars (FeO-biochar and FeO-pyrochar) derived from biomass waste were functionalised in two different ways with iron chloride for comparation. Batch and dynamic parameters were optimised to achieve >99% As(V) removal efficiency. Experimental data were best described by the pseudo-second order kinetic model, while multi-stage diffusion appeared to limit mass transfer of As(V). Among the isotherm models evaluated, the Freundlich model best described the experimental results with high correlation coefficients (R2 ≥ 0.94) for both adsorbents. Monolayer adsorption capacities were found to be 4.34 mg/g and 8.66 mg/g for FeO-biochar and FeO-pyrochar, respectively. Batch studies followed by instrumental characterisation of the materials indicated the removal mechanisms involved to be electrostatic interactions (outer-sphere), OH- ligand exchange (inner-sphere complexation) and hydrogen bonding with functional groups. Higher pHpzc (9.1), SBET (167.2 m2/g), and iron/elemental content for the FeO-pyrochar (compared with the FeO-biochar) suggested that both surface chemistry and porosity/surface area were important in adsorption. Dynamic studies showed FeO-pyrochar can be used to remove As(V) from groundwater even at low 'environmental' concentrations relevant to legislative limits (<10 µg/L), whereby 7 g of FeO-pyrochar was able to treat 5.4 L groundwater.

Removal of benzotriazole derivatives by biochar: Potential environmental applications.

Benzotriazole and its derivatives (BTAs) are commonly present in wastewater due to their extensive use in industrial processes, yet their removal is still unexplored. Here, we test the removal of these pollutants using two functionalised biochars, synthesised from wild plum (WpOH) and apricot (AsPhA) kernels. The aim of this work was to optimise the adsorption process against various BTAs (i.e., benzotriazole (BTZ), 4-hydroxy-1H-benzotriazole (OHBZ), 4-methyl-1H-benzotriazole (4 MBZ), 5-methyl-1H-benzotriazole (5 MBZ), 5-chloro-1H-benzotriazole (ClBZ), 5,6-dimethyl-1H-benzotriazole (DMBZ)), and determine the adsorption mechanisms at play, using real wastewater matrices. Batch studies showed that the optimal adsorption pH ranged between 4 and 6 for WpOH and AsPhA, respectively, and equilibrium was reached after 240 min. The kinetic models that best described the adsorption process were in the following order: Elovich model > pseudo-second order model > pseudo-first order model. The equilibrium data showed the highest correlation with the Freundlich isotherm, indicating multilayer adsorption. The maximum adsorption capacity obtained in mixtures was 379 mg/g on WpOH and 526 mg/g on AsPhA. The mechanistic work revealed that the BTAs became bound to the biochar primarily through H-bonding, n-π and π-π EDA interactions. In wastewater, obtained before and after conventional treatment, the concentration of OHBZ and BTZ was reduced by >40%, while the concentration of the other compounds studied fell below the detection limit (∼2.0-90 ng/L). Finally, using a Vibrio fischeri assay, we showed that adsorption onto AsPhA significantly reduced the relative toxicity of both raw and treated wastewater.

Enhanced phosphate removal and potential recovery from wastewater by thermo-chemically calcinated shell adsorbents.

Shell from the seafood processing industry is an under-utilised waste resource worldwide. Calcite, the major component of shell is commonly used in wastewater treatment for the removal of phosphorus (P). Here, mussel and oyster shell-based adsorbents (MSB and OSB) were used for removal of P as phosphate (PO43-) from aqueous solution and secondary wastewater, following preparation through chemical calcination at 700 °C. Batch adsorption experiments were carried out to identify the effects of various operating parameters (e.g., pH, dosage, contact time, initial concentration of P ions, co-existing ions), while a desorption study helped to understand the availability of the bonded P. The optimal contact time for PO43- removal was 120 min using both adsorbents with the dose at 200 mg. Characterisation of the adsorbent was performed using SEM-EDX, pHpzc, BET, FTIR and XRD. The XRD analysis showed that both calcite and lime were present on the surface of the shell particles. P was adsorbed effectively through inner-sphere complexation and surface microprecipitation mechanisms, while an enhanced maximum P adsorption capacity of 12.44 mg/g for MSB and 8.25 mg/g for OSB was reached. The Redlich-Peterson isotherm model fitted well with the equilibrium isotherm data (R2 ≥ 0.97) which also suggested a heterogenic surface. The desorption study (on the saturated adsorbent) found that ~97% of bonded P could be plant available in soil. These results suggest that a shell-based adsorbent can serve as a promising material for P removal from real wastewater effluent and subsequently could be used as a soil conditioner.

Synergistic effect of Fenton oxidation and adsorption process in treatment of azo printing dye: DSD optimization and reaction mechanism interpretation.

The main challenges to overcome within the Fenton process are the acidic pH as an optimal reaction condition, sludge formation in neutral pH medium and high toxicity of treated printing wastewater due to the generation of contaminating by-products. This research discusses the catalytic activity of homogeneous (FeSO4/H2O2) and heterogeneous (Fe2(MoO4)3/H2O2) Fenton processes in treatment of Yellow azo printing dye in synthetic aqueous solution and real printing effluent, with an integration of adsorption on functionalized biochar synthesized from wild plum kernels. The definitive screening design (DSD), was used to design the experiment. Independent variables were initial dye concentration (20-180 mg L-1), iron concentration (0.75-60 mg L-1), pH (2-10) and hydrogen peroxide concentration (1-11 mM). Higher decolourization efficiency of 79% was obtained within homogeneous Fenton treatment of printing wastewater, in comparison to heterogeneous Fenton treatment (54%), after a reaction time of 60 min. Same trend of mineralization degree was established: COD removal was 59% and 33% for homogeneous and heterogeneous Fenton process, respectively. The application of adsorption treatment has achieved significant advantages in terms of toxicity reduction (95%) and decolourization efficiency (90% of TOC removal and 22% of dye removal) of treated samples, even at neutral pH medium. Degradation mechanisms within Fenton and adsorption processes were proposed based on the qualitative gas chromatography/mass spectrometry analysis, physico-chemical properties of dye degradation products and functionalized biochar. Overall, the homogeneous Fenton/adsorption combined process can be potentially used as a treatment to remove azo dyes from contaminated water.

Circular economy based landfill leachate treatment with sulphur-doped microporous biochar.

There is now increasing interest in the creation of a more 'circular economy', with a particular aim to eliminate waste - by design, within which products are optimised to be reused, restored or returned. Here, a sulphur functionalised microporous biochar was synthesised from an abundant biomass waste material (cherry kernels), for the selective removal of Pb(II) from landfill leachate as a representative heavy metal. The production process utilises renewable waste material and removes toxic chemicals. Characterisation of the biochar showed that pyrolysis and functionalisation formed an adsorbent with a microporous structure and rich surface chemical functionality. The adsorption process was optimised using a 'response surface methodology - Box-Behnken Design'. Lead removal efficiency approached 99.9% under optimised experimental conditions, i.e., where the solution pH was 6.0, the biochar dose was 4.0 g/L and the contact time was 47 min. The adsorption process was best described using a Freundlich model. The maximum amount of Pb(II) adsorbed was 44.92 mg/g. The main adsorption mechanisms occurred through outer-sphere (electrostatic attraction) and inner-sphere complexation. Desorption studies showed that three successful regeneration cycles (with acidic deionised water) could be used post pyrolysis. The biochar removed 97% of Pb(II) from landfill leachate samples, as compared to 9.4%, and 7.6% for two commercial activated carbon adsorbents. These findings demonstrate the high selectivity of this biochar towards Pb(II) and its applicability even in the presence of high concentrations of many potentially interfering inorganic and organic ions and compounds.

Removal behaviour of NSAIDs from wastewater using a P-functionalised microporous carbon.

Diclofenac (DCF), naproxen (NPX) and ibuprofen (IBF) are three of the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs) worldwide. They are widely detected in natural waters due to their persistence in wastewater treatment, and their removal is desirable in future wastewater management worldwide. In this study, "acid catalyst" functionalisation and subsequent carbonisation were adopted to synthesise a P-doped microporous carbonous adsorbent (CScPA) for NSAID removal. The CScPA was evaluated in depth for its adsorption performance (i.e., isotherms, kinetics and thermodynamics of adsorption at lab-scale). The CScPA had a large surface area (791.1 m2/g) and good porosity (0.392 cm3/g), which facilitated a high maximum adsorption capacity of 62.02 mg/g for a NSAID mixture. Thermodynamic data indicated that the adsorption of these NSAIDs was an endothermic process determined by physisorption (low-energy interactions). XPS analysis revealed the specific interactions involved in the adsorption process, including π-π and n-π electron donor-acceptor (EDA) interactions and hydrogen (H-) bonding. The Freundlich isotherm and Elovich kinetic model provided the best fit to the experimental results, which indicated surface heterogeneity (of the CScPA) and cooperative adsorption mechanisms. The adsorption process was shown to have potential to be applied to real wastewater effluent containing NSAIDs at low environmentally relevant concentrations (removal reached > 90% at 10 µg/L). Analysis of different implementation and cost related factors suggested that the CScPA has the potential for use with "real-world" water matrices, offering a sustainable treatment process for pharmaceutical remediation in wastewater.

Reply to comments on "Low-cost chitosan-calcite adsorbent development for potential phosphate removal and recovery from wastewater effluent" by Pap et al. [Water research 173 (2020) 115573].

This letter is in response to the comments of Dr Hu and Dr Zhang on "Low-cost chitosan-calcite adsorbent development for potential phosphate removal and recovery from wastewater effluent" (Pap et al., 2020). We thank Dr Hu and Dr Zhang for their interest and comments, and having reflected, we wish to provide some clarification.

Low-cost chitosan-calcite adsorbent development for potential phosphate removal and recovery from wastewater effluent.

Phosphorous (P) recovery from wastewater will become increasingly vital in the future as terrestrial rock phosphate deposits are expended. Effective management of P as a critical resource will require new techniques to recover P from wastewater, ideally in a form that can be used in agriculture as fertiliser. In this study, batch and fixed-bed column conditions were tested using a novel KOH deacetylated calcite-chitosan based adsorbent (CCM) for P removal from aqueous solutions and wastewater effluents. The unique characteristics of this adsorbent as a phosphate adsorbent were the result of rich surface functionality (amine and sulphur functional groups of the chitosan and proteins) and the CaCO3 content (providing donor ligands; and additionally beneficial if the material were used as fertiliser, buffering soil acidification caused by nitrogen application). The maximum P adsorption capacity was determined to be 21.36 mgP/g (at 22 °C) and the endodermic process reached equilibrium after 120 min. The experimental data was best described using a Langmuir isotherm and a pseudo-second order kinetic model. The diffusion kinetic analysis highlighted the importance of both film and intraparticle mass-transport. Material characterisation suggested that the adsorption process involved interactions between P and functional groups (mostly -NH3+) due to electrostatic interaction on the chitosan chain or involved ligand exchange with CO32-. Analysis of materials using X-Ray Powder Diffraction (XRPD) and Thermogravimetric Analysis (TGA) indicated a microprecipitation-type mechanism may occur through the formation of hydroxylapatite (Ca5(PO4)3(OH)). Desorption studies demonstrated that the P-laden CCM (derived from crab carapace) had the potential to be reused in soil amendment as a slow-release P fertiliser. The effects of different operating parameters were explored in a fixed-bed column, and the experimental data fitted well to the Clark model (R2 = 0.99). The CCM also showed excellent P adsorption potential from secondary and final wastewater effluent in dynamic conditions, even at low P concentrations. Finally, a scale-up approach with cost analysis was used to evaluate the price and parameters needed for a potential large-scale P recovery system using this adsorbent.

Synthesis optimisation and characterisation of chitosan-calcite adsorbent from fishery-food waste for phosphorus removal.

Here, Box-Behnken design (BBD) approaches were utilised to optimise synthesis methodology for the chitosan-calcite rich adsorbent (CCM) made from fishery-food waste material (crab carapace), using low-temperature activation and potassium hydroxide (KOH). The effect of activation temperature, activation time and impregnation ratio was studied. The final adsorbent material was evaluated for its phosphorus (P) removal efficiency from liquid phase. Results showed that impregnation ratio was the most significant individual factor as this acted to increase surface deacetylation of the chitin (to chitosan) and increased the number of amine groups (-NH2) in the chitosan chain. P removal efficiency approached 75.89% (at initial P concentration of 20 mg/L) under optimised experimental conditions, i.e. where the impregnation ratio for KOH:carapace (g/g) was 1:1, the activation temperature was 105 °C and the activation time was 150 min. Predicted responses were in good agreement with the experimental data. Additionally, the pristine and CCM material were further analysed using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), Brunauer-Emmett-Teller technique (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). Characterisation showed enhancements in surface chemistry (introducing positively charged amine groups), textural properties and thermal stability of the CCM.

Methodological Aspects of Extraction, Phytochemical Characterization and Molecular Docking Studies of Salix caprea L. Bark and Leaves.

Contents of twelve selected bioactive substances and antioxidant potential of Salix caprea L. extracts were compared in its two vegetative organs (bark and leaves) and in terms of different ethanol/water mixtures used for extraction (30-70% aq, ethanol) and extraction time (30 min; 24, 48 and 72 h). The extracts were characterized by High Pressure Liquid Chromatography (HPLC), and total phenolics and flavonoids were determined spectrophotometrically. All secondary metabolites identified in Salix caprea L. extracts (gallic, chlorogenic and vanillic acid, epicatechin, rutin, quercetin and naringenin) were found more accumulated in bark. Salicin and p-hydroxybenzoic acid were detected in bark and ferulic, trans-cinnamic and p-coumaric acid in leaves extracts only. Rutin was most abundant bioactive compound both in bark (1.71 g/100 g of de) and leaves extracts (0.434 g/100 g of de). Bark extract with highest bioactive substances contents was obtained with 70% aq. ethanol as most suitable solvent during extraction time of 48 h. Molecular docking showed salicin to have similar affinity toward COX-2 as acetylsalicylic acid, but lower toward COX-1.

Ionisable emerging pharmaceutical adsorption onto microwave functionalised biochar derived from novel lignocellulosic waste biomass.

Functionalised biochar (WpOH) was prepared from wild plum kernels using simultaneous pyrolysis and microwave potassium hydroxide (KOH) functionalisation. This was then applied to the removal (from water) of an ionisable pharmaceutical - naproxen (NPX). Characterization of the WpOH was carried out using pHpzc, SEM/EDX, BET, FTIR, XRD, and the principle adsorption mechanisms were thoroughly studied. A pseudo-second order kinetic model best described the reaction kinetic behaviour, and the Langmuir isotherm provided the best fit to the results. The maximum adsorptive interaction (73.14 mg/g) occurred between pH 5 and 7 through electrostatic attraction (the main interaction mechanism) between the negatively charged NPX and the positively charged WpOH functional groups. In addition, hydrogen-bonding and electron-donor-acceptor (EDA) interactions were important. In a competitive study, using NPX and carbamazepine (a basic/amphoteric drug), the different nature/structure of the two compounds resulted in slight competitive adsorption. The results demonstrate the potential for wild plum kernel biochar to be used in the efficient removal of emerging contaminants such as pharmaceuticals from water.

Efficient removal of priority, hazardous priority and emerging pollutants with Prunus armeniaca functionalized biochar from aqueous wastes: Experimental optimization and modeling.

This paper investigates the ability of the phosphoric acid functionalized Prunus armeniaca stones biochar (AsPhA) prepared by thermochemical activation to remove lead (Pb2+), cadmium (Cd2+), nickel (Ni2+), naproxen and chlorophenols from aqueous wastes. The engineered biochar was characterized using the Scanning Electron Microscopy, Energy-dispersive X-ray Spectroscopy, Fourier Transform Infrared Spectroscopy and Brunauer, Emmett and Teller technique. The batch studies were performed by varying the initial pH of the solution (2-9), adsorbent dosage (0.2-10gL-1), contact time (5-60min), temperature (22, 32 and 42°C) and initial adsorbate concentration (5-500mgL-1). With the optimal process conditions, the adsorption efficiency was over 95% (100mgL-1). The results were fitted with three kinetic and three equilibrium theoretical adsorption models. The adsorption process has good correlation with pseudo-second-order reaction kinetics. Adsorption mechanism was found to be controlled by pore, film and particle diffusion, throughout the entire adsorption period. The monolayer adsorption capacities were found to be 179.476, 105.844 and 78.798mgg-1 for Pb2+, Cd2+ and Ni2+, respectively. Thermodynamic parameters such as Gibbs energy, enthalpy and entropy were also calculated. Additionally, preliminary results indicated a strong affinity of the biochar for selected organic micropollutants: naproxen and chlorophenols. Based on desorption study results, biochar was successfully regenerated in 3cycles with diluted phosphoric acid produced as a waste stream during washing of the biochar after thermochemical activation. The experimental results were applied in a two-stage completely stirred tank reactor design. Cost estimation of AsPhA production substantiated its cost effectiveness and adsorption costs of selected pollutants were 5 times lower than with the commercial activated carbons. Based on the low-cost and high capacity, engineered biochar can be used as a highly efficient eco-friendly adsorbent for removal of heavy metal and organic micropollutants from wastewaters systems.

The emission of BTEX compounds during movement of passenger car in accordance with the NEDC.

The results of the research in the field of benzene, toluene, ethylbenzene and xylene isomers (BTEX) concentrations in exhaust gases of spark ignition engines under different operating conditions are presented in this paper. The aim of this paper is to gain a clearer insight into the impact of different engine working parameters on the concentrations of BTEX. The experimental investigation has been performed on the SCHENCK 230 W test stand with the controlled IC engine. The engine operating points have been chosen based on the results of a simulation and they are considered as the typical driving conditions according to the New European Driving Cycle. Concentration levels of BTEX compounds in exhaust gas mixtures have been determined by gas chromatography technique by using the combination of Supelcowax 10-Polyethylene glycol column and the PID detector. Based on the experimental research results, the emission model of BTEX compounds has been defined by the simulation of movement of a Fiat Punto Classic passenger car in accordance with the NEDC cycle. Using the results obtained within the simulation, the official statistics on the number of gasoline-powered cars on the territory of the Republic of Serbia and the European Commission data on the annual distance traveled by car, the amounts of BTEX compounds emitted annually per car have been estimated, as well as the emissions of the entire Serbian car fleet.

The occurrence of selected xenobiotics in the Danube river via LC-MS/MS.

Having in mind that there is a general lack of monitoring plans and precaution measures in the developing countries and that the Danube is the second longest river in Europe, the estimation of the relevant concentration levels of unregulated xenobiotics is a topic of interest both on local and international level. The selected pharmaceuticals, caffeine, and benzotriazole presented in the collected water samples from seven representative locations around the territory of Novi Sad, Serbia, during 1-year period, were analyzed with the use of solid-phase extraction followed by the liquid chromatography coupled with triple quad tandem mass spectrometry. The most frequently detected compounds were caffeine and carbamazepine in the concentrations up to 621 and 22.2 ng/L, respectively, while the maximum concentration of the analyzed pharmaceuticals was obtained for ibuprofen (60.1 ng/L). The presence of benzotriazole along the analyzed section of the river was confirmed in the concentration levels up to 26.7 ng/L. Although sulfamethoxazole and desmethyldiazepam were detected at trace levels (0.22 and 3.41 ng/L, respectively); the presence of these pharmaceuticals in complex mixtures should not be neglected. Due to the frequent detection caffeine, carbamazepine, ibuprofen, and benzotriazole could be proper candidate for hydrophilic anthropogenic markers for quantification of wastewater contamination in surface water in the analyzed Danube section.