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This monograph provides comprehensive coverage of technologies which integrate adsorption and biological processes in water and wastewater treatment. The authors provide both an introduction to the topic as well as a detailed discussion of theoretical and practical considerations. After a review of the basics involved in the chemistry, biology and technology of integrated adsorption and biological removal, they discuss the setup of pilot- and full-scale treatment facilities, covering powdered as well as granular activated carbon. They elucidate the factors that influence the successful operation of integrated systems. Their discussion on integrated systems expands from the effects of environmental to the removal of various pollutants, to regeneration of activated carbon, and to the analysis of such systems in mathematical terms. The authors conclude with a look at future needs for research and develoment. A truly valuable resource for environmental engineers, environmental and water chemists, as well as professionals working in water and wastewater treatment.

Abstract IntroductionAspirin overdose causes acid–base disturbances and organ dysfunction. Management is guided by research reported over 50 years ago when chronic aspirin toxicity was common and accounted for significant morbidity. We investigate our experience of aspirin overdose and the effectiveness of charcoal and bicarbonate administration over 20 years.MethodsThis is a retrospective series of acute aspirin overdose from two toxicology units from January 2000 to September 2019. Acute aspirin ingestions > 3000 mg were identified in each unit’s database. Excluded were cases of chronic exposure, hospital presentation > 24 hours after ingestion, and cases without a salicylate concentration. Included in our analysis was demographic data, clinical effects, investigations, complications, and treatment.ResultsThere were 132 presentations in 108 patients (79 females (73%)). The median age was 28 years (range: 13–93 years). The median dose ingested was 7750 mg (IQR: 6000–14,400 mg). There were 44 aspirin-only ingestions. Mild toxicity (nausea, vomiting, tinnitus or hyperventilation) occurred in 22 with a median dose of 160 mg/kg. Moderate toxicity (acid–base disturbance, confusion) occurred in 16 with a median ingested dose of 297 mg/kg. There were no cases of severe toxicity (coma or seizures) due to aspirin alone. The median peak salicylate concentration was 276 mg/L (IQR: 175–400 mg/L, range: 14–814 mg/L). There was a moderate association between dose ingested and peak concentration (Pearson r = 0.58; 95% CI 0.45–0.68). Activated charcoal was administered in 36 (27%) cases, which decreased the median peak salicylate concentration (34.2 to 24.8 mg/L/g (difference: 9.4, 95% CI: 1.0–13.1)). Bicarbonate was administered in 34 (26%) presentations, decreasing the median apparent elimination half-life from 13.4 to 9.3 h (difference: 4.2 h, 95% CI: 1.0–6.5 h).ConclusionsAcute aspirin overdose caused only mild to moderate effects in this series. Early administration of activated charcoal decreased absorption and use of bicarbonate enhanced elimination.

In this study, granulated activated charcoal (GAC) and bio charcoal (BC) is used as a filler in P3 biosand bag filter to study their filtration performance against a range of fluoride impurities from 1–1400 mg/L. A set of experiments are done to analyze the filtration efficiency of the sandbag filter against fluoride impurities after incorporating different amounts (e.g., 0.2, 2 kg) and a combination of GAC and BC. A combination of filler GAC and BC (1 kg each) have exhibited excellent results with 100% fluoride removal efficiency against 5 mg/L fluoride impurities for an entire experimental time of 165 min. It is because of the synergetic effect of adsorption caused by the high surface area (739 m2/g) of GAC and hydroxyapatite groups in BC. The data from remediation experiments using individual GAC and BC are fitted into the Langmuir and Freundlich Isotherm Models to check their adsorption mechanism and determine GAC and BC’s maximum adsorption capacity (Qm). The remediation data for both GAC and BC have shown the better fitting to the Langmuir Isotherm Model with a high R2 value of 0.994 and 0.970, respectively, showing the excellent conformity with monolayer adsorption. While the GAC and BC have presented negative Kf values of −1.08 and −0.72, respectively, for Freundlich Model, showing the non-conformity to multilayer adsorption. The Qm values obtained from Langmuir Model for GAC is 6.23 mg/g, and for BC, it is 9.13 mg/g. The pH study on adsorption efficiency of individual GAC and BC against 5 mg/L of fluoride impurities indicates the decrease in removal efficiency with an increase in pH from 3 to 9. For example, BC has shown removal efficiency of 99.8% at pH 3 and 99.5% at pH 9, while GAC has exhibited removal efficiency of 96.1% at pH 3 and 95.9% at pH 9. Importantly, this study presents the significance of the synergetic application of GAC and BC in the filters, where GAC and BC are different in their origin, functionalities, and surface characteristics.

[Display omitted] •ACC is suitable for the extraction and concentration of ignitable liquid residues.•The sampling ability of ACS and ACC are comparable.•The distance between the skin and the sorbent strongly influences the collection.•The space between the hand and the glove or bag impacts the sampling of gasoline. Arsonists may use ignitable liquids to start, accelerate and amplify fires. The sampling of volatiles present on the hands of suspected arsonists is therefore sometimes carried out in the course of the investigation of (possible) deliberate fires. Several collection protocols have been proposed, relying on the concentration of volatiles by the transfer on PVC gloves and further passive headspace extraction with Activated Charcoal Strips (ACS). Previous research findings assessing the use of Activated Carbon Cloth (ACC) – initially developed for the adsorption of gas in military applications – opens the path to new perspectives regarding the extraction and the concentration of ignitable liquid residues in general, and for the sampling on hands in particular. Five alternative methods (four relying on the use of ACC and one on ACS) were considered for the collection of gasoline traces present on the hands and their subsequent analysis by gas chromatography – mass spectrometry. Gasoline was deposited onto the palms of volunteers to study the differences between the collection method using ACS and those using ACC. For the latter, either the volunteer hands were placed in nylon bags with an ACC on the palm or suspended, or, powder-free latex gloves were used, with an ACC on the palm or in a separate extraction, with the glove in a nylon bag and the ACC suspended. The results showed that the background contamination was not distinguishable between ACS and ACC and their sampling ability was comparable. The two methods relying on the deposition of ACC directly on the surface of the palm where gasoline was deposited showed significantly higher collection capacity than other methods, provided that the ACC was in direct contact with the contaminated zone. The results showed that three main factors affected the collection of gasoline on the hands: the distance between the skin and the sorbent (ACC or ACS) in case of direct concentration of volatiles on the sorbent, the exposure time, and the space between the hand and the glove or bag (i.e. the headspace volume). This research opens new perspectives for the sampling of ignitable liquid residues through the use of ACC. It corroborates the perceived potential of ACC for the extraction and concentration of volatile compounds, particularly for fire debris analysis purposes. While the experiments were focused on the collection of gasoline on hands, the results provide valuable information in a more general way for the sampling of fire debris.

Used pesticides result in soil pollution, which potentially seep into groundwater, posing risks to human and animal health. The current study examines the use of a new cheap material for removing four commonly used pesticides from polluted groundwater before use for drinking. These pesticides are Malathion, Methomyl, Abamectin, and Thiamethoxam. Activated charcoal obtained from the trunk of “Salix mucronata” trees is introduced for removing these pesticides by surface adsorption. Activation treatment using gold-nitrate solution is introduced to enhance the charcoal adsorption capacity, because removal of pesticides is difficult due to their large-sized molecules and lack of obvious surface electrostatic charges. Physical and chemical properties of the studied pesticides and the activated charcoal were determined. Batch experiments tested the effects of solution pH, contact time, dose of charcoal, and initial concentrations on the charcoal adsorption capacity. Langmuir adsorption linear isotherm test was done to use for the prediction of adsorption behavior. Fixed-bed column experiments tested clean-up of polluted water using charcoal filter under steady flow. Gold-nitrate activated charcoal adsorption capacities were almost three times higher than other charcoals for the same pesticides at the same initial concentrations. Maximum adsorption capacities achieved in the current study were 16.17, 14.59, 9.55, and 8.99 mg/g, respectively, at the initial concentrations of 50.0 mg/l. Meanwhile, treatment times in steady-flow fixed-bed columns were much lower compared to other studies. Preparation cost of gold-nitrate activated charcoal in the current study was lower than other adsorbents. The charcoal introduced in this study is recommended for use in low-cost removal of pesticides from polluted groundwater on the national scale, including small treatment units for rural communities with limited facilities.

Background: Tooth whitening is a widely sought-after cosmetic procedure, with various at-home and professional treatments available. This study compares the whitening efficacy of an activated charcoal toothpaste and a 6% hydrogen peroxide whitening pen under controlled in vitro conditions. Methods: Twenty freshly extracted human teeth were stained with a coffee solution and divided into two groups. Group A underwent daily applications of activated charcoal toothpaste for 30 days, while Group B received a single 5 min application of a 6% hydrogen peroxide whitening pen. Tooth color was assessed using the VITA Classical A1-D4 Shade Guide at baseline, mid-treatment, and post-treatment for Group A and at baseline and immediately after treatment for Group B. Results: The activated charcoal toothpaste exhibited a gradual whitening effect, with the most significant improvements occurring within the first two weeks (p < 0.01), after which the whitening effect plateaued. In contrast, the hydrogen peroxide whitening pen produced immediate and substantial whitening (p < 0.001). Statistical analysis using the Wilcoxon signed-rank test and Mann–Whitney U test confirmed the superior efficacy of the hydrogen peroxide treatment. Conclusions: The hydrogen peroxide whitening pen was significantly more effective in achieving rapid and substantial whitening compared to the activated charcoal toothpaste, which provided gradual but limited improvements. Further clinical studies are needed to evaluate the long-term color stability.

Groundwater is a vital source of potable water worldwide. However, contamination by radionuclides and heavy metals, originating from natural and industrial sources, poses significant risks to humans, animals, and plants. This study focuses on the purification of radioactively contaminated groundwater using lead-modified activated charcoal. The charcoal was synthesized by incorporating lead ions from a lead acetate solution into the crystal lattice of activated charcoal under controlled carbonization conditions, varying temperature, and lead acetate concentrations. Tectanium-99 (beta rays) and pertectanium-m99 (gamma rays) were employed in experimental setups to simulate contamination. Comprehensive characterization of the lead-modified activated charcoal was conducted using SEM, FTIR, BET, and zeta potential analyses to elucidate its adsorption mechanism. Batch experiments assessed the removal efficiency of radiation from synthetically contaminated water, examining the effects of pH, contact time, and contaminant concentration. The results revealed that the lead-modified activated charcoal achieved up to 98% radiation removal using just 0.1 grams within 15 minutes at a pH of 3.0. Building on these promising results, the study progressed to a fixed-bed column setup, a practical solution for larger-scale applications. A dual-column system, packed with lead-modified activated charcoal, was designed to ensure complete radiation removal. The performance of the fixed-bed system was evaluated, focusing on flow rate and bed height. Optimal conditions for maximal radiation removal were determined to be a flow rate of 15 mL/min and a bed height of 15 cm. This research highlights the development of a novel, cost-effective material for purifying radioactively contaminated water and demonstrates the successful design of an adsorption column that maximizes the material’s efficiency for real-world applications.

The current study addresses the removal of an emerging environmental contaminant (primidone) in batch adsorption experiments using commercial-grade powdered activated charcoal (PAC). The experiments for the removal of primidone were performed to identify the effect of various adsorption parameters. The second-order rate expression best represented the adsorption kinetics data. The Freundlich isotherm equation was best fitted to the experimental adsorption data at equilibrium for removal of primidone using PAC. The values for change in entropy (Δ S o ) were positive, which indicates that the degree of freedom of the process increases. The negative values of change in enthalpy (Δ H o ) and change in Gibb’s free energy (Δ G o ) indicate that the physical adsorption is a dominant phenomenon, and the process is feasible and spontaneous. The negative value of Δ H o also represented the exothermicity of the adsorption process. The Taguchi optimization technique calculated the influence of variation of different process parameters, viz., initial pH (pH 0 ), PAC dosage ( m ), initial adsorbate concentration ( C 0 ), solution temperature ( T ), and process contact time ( t ), on the removal of primidone by adsorption from aqueous solution. Each of the above parameters was examined at three levels to study their effects on the adsorptive uptake of primidone using PAC ( q e , mg g −1 ), and the optimum value necessary to maximize q e was determined. The findings from the ANOVA indicate that the PAC dose ( m ) is the most notable parameter contributing 62.16% to q e and a 71.96% to the signal to noise (S / N) ratio data, respectively. The confirmation experiments performed at the optimum parameter condition validated the applicability of the Taguchi design of experiments. The percent removal and adsorptive uptake at the optimal condition were 86.11% and 0.258 mg g −1 , respectively.

This study investigated the potential of horizontal subsurface flow constructed wetlands (HSSF-CWs) and open raceway ponds (RWPs) operated under different regimes (plants, impregnated activated charcoal (IAC), and algae) for long-term nitrogen removal to control eutrophication problems. For experimental purposes, five mesocosms HSSF-CWs and two RWPs were set up in Wuxi, China, a temperate climate zone. Three HSSF-CW units were cultivated with different regions’ plant species including Nasturtium officinale, Juncus effusus, and Brassica juncea, whereas the one unit packed with IAC and the fifth was left as a control, while two species of algae (Spirogyra and C. pyrenoidosa) were cultured in RWPs. All the amendments tested in this study were almost equally effective for long-term nitrogen removal. The results demonstrated that more than 75.7, 88, and 66%, removal of TN, NH4+–N, and NO3-–N was achieved by the HSSF-CWs, packed with IAC and N. officinale. Concerning RWPs, both algal species showed almost similar results but slightly lower than others, which may be attributed to the less compatibility with the environment. It was observed that nitrogen removal performance was higher in the winter-spring (March–April) season as compared with winter (January–February). Moreover, all plants, particularly N. officinale growth, were quite steadier than others. The present study validates the impression that both treatment systems were potentially effective in long-term nitrogen removal from sewage and could be considered beneficial to control the eutrophication.

Tannery wastewater contains a significant amount of chemical compounds, including toxic substances. Due to the toxicity and negative environmental effects of these tannery effluents, mandatory treatment is necessary. The main objective of this study was to treat effluent from an artisanal tannery in the city of Fez (Morocco) using the adsorption process with activated charcoal derived from olive pomace. The physicochemical characterization of tanning water included several parameters, such as chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), suspended solids (SS), sulfate ions (SO42-), nitrate, and chromium Cr(VI). The analyses show that the adsorption process reduced nitrate by 57.54%, sulfate by 94.08%, TKN by 74.84%, COD by 68.18%, Cr by 91.27%, and Cr (VI) by 89.78%. The activated charcoal was characterized before and after tannery effluent treatment using various techniques, including FT-IR, SEM, and EDX. From the above, it can be inferred that using activated carbon made from olive pomace has the potential to reduce tannery effluent pollution parameters. This innovative approach demonstrates that competitive results can be achieved without sacrificing economic viability, thereby promoting sustainable practices in the treatment of industrial liquid waste and wastewater treatment plants.