scholarly journals Models of adsorption of natural contaminants from treated water for municipal purposes on powdered activated carbon

2020 ◽  
pp. 1-14
Author(s):  
Andrzej Bielski

The paper investigates whether time and doses of powder activated carbon (PAC) effect adsorption rates of organic contaminants from water and proposes a new model of volume adsorption. Depending on the nature of the organic compounds present in water, a general description of the adsorption process may require a linear combination of adsorption models running at different rates and at different parameters of adsorption isotherms. The model showed a good fit with the measured data and could be used in designing adsorption units at water or wastewater treatment plants. The proposed set of model equations enables to predict the effects of PAC adsorption in both plug flow reactors and homogeneous reactors.

2013 ◽  
Vol 470 ◽  
pp. 11-14 ◽  
Author(s):  
Rui Xin Guo ◽  
Zhi Liang Wang ◽  
Guo Ping Li ◽  
Jian Qiu Chen

The adsorption of cefradine was carried out using biological adsorbents of powder and carbon prepared from orange peels, an agriculture by-product. The equilibrium was easily reached in less than 10 minutes, with adsorption rates of more than 98%. Cefradine showed a firm combination to the adsorbent, which could hardly be damaged or affected by pH values. After equilibrium was reached within 1 h, no desorption behavior was observed in the next 30 minutes. The adsorption process could be well fitted thermodynamically to both Freundlich and Langmuir equations. Similar results could also be obtained using ashes of orange peel, as well as carbon prepared from pistachio and peanut hull, indicating an attractive option to treat industrial wastewater.


2015 ◽  
Vol 802 ◽  
pp. 425-430
Author(s):  
Muhd Nazmi Ismail ◽  
Hamidi Abdul Aziz ◽  
Mohd Azmier Ahmad ◽  
Nik Athirah Yusoff

In this present study, rubber seed-coated activated carbon (RSCAC) was used as a natural adsorbent to remove basic (MB), acid (MR) and reactive (RBV) dyes using batch process. Each dye in the adsorption process was tested at different initial concentration from 50-500 mg/l. Different dyes showed different percentage removals. The highest removal was recorded by MB which was up to 99.9 %. The experimental data was analyzed with Langmuir and Freundlich adsorption models. The data fitted well with Langmuir. The adsorption capacity were 332.99, 210.33 and 155.37 mg/g for MB, MR and RBV, respectively.


2016 ◽  
Vol 74 (12) ◽  
pp. 2927-2934 ◽  
Author(s):  
Arturo Trapote ◽  
Mariano García ◽  
Daniel Prats

Siloxanes present in the biogas produced during anaerobic digestion in wastewater treatment plants (WWTPs) can damage the mechanism of cogeneration heat engines and obstruct the process of energy valorization. The objective of this research is to detect the presence of siloxanes in the biogas and evaluate a procedure for their elimination. A breakthrough curve of a synthetic decamethylcyclopentasiloxane on an experimental bed of activated carbon was modeled and the theoretical mathematical model of the adsorption process was adjusted. As a result, the constants of the model were obtained: the mass transfer constant, Henry's equilibrium constant, and the Eddy diffusion. The procedure developed allows the adsorption equilibrium of siloxanes on activated carbon to be predicted, and makes it possible to lay the basis for the design of an appropriate activated carbon module for the elimination of siloxanes in a WWTP.


1991 ◽  
Vol 23 (1-3) ◽  
pp. 349-356 ◽  
Author(s):  
B. N. Jacobsen ◽  
N. Nyholm ◽  
B. M. Pedersen ◽  
O. Poulsen ◽  
P. Østfeldt

The microbial degradation of pentachlorophenol (PCP) and lindane in the activated sludge process was studied. 14 steady-state experimental runs were performed in single-stage activated sludge reactors under various operating conditions. PCP and lindane mixed with three other model compounds were added to the feed as secondary substrate, with synthetic sewage as primary substrate. Reactor concentrations (dissolved) of the model compounds were in the range of 1-200 µg/l. For PCP, the biodegradation increased with increasing solids retention time SRT. This indicates that degradation takes place by catabolic growth of a specific fraction of the biomass. At SRT > 8 days the 1st order biodegradation rate constant was about 2.5 × 10−3 1/(mg MLSS day) at a temperature of 15°C. For lindane, the reverse relation was observed. Increased degradation was observed with increasing degradation of primary substrate. This indicates the presence of other mechanisms such as co-metabolism or probably reductive dechlorination. In relation to upgrading of wastewater treatment plants to biological nutrient removal, xenobiotic compounds behaving like PCP are expected to be increasingly degraded. For compounds behaving like lindane, co-metabolic activity can be stimulated in plug-flow reactors rather than CSTR, and anaerobic zones in the activated sludge process may play an important role for the degradation.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4483
Author(s):  
Yuyingnan Liu ◽  
Xinrui Xu ◽  
Bin Qu ◽  
Xiaofeng Liu ◽  
Weiming Yi ◽  
...  

In this study, corn cob was used as raw material and modified methods employing KOH and KMnO4 were used to prepare activated carbon with high adsorption capacity for mercury ions. Experiments on the effects of different influencing factors on the adsorption of mercury ions were undertaken. The results showed that when modified with KOH, the optimal adsorption time was 120 min, the optimum pH was 4; when modified with KMnO4, the optimal adsorption time was 60 min, the optimal pH was 3, and the optimal amount of adsorbent and the initial concentration were both 0.40 g/L and 100 mg/L under both modified conditions. The adsorption process conforms to the pseudo-second-order kinetic model and Langmuir model. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Zeta potential characterization results showed that the adsorption process is mainly physical adsorption, surface complexation and ion exchange.


2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Marion Woermann ◽  
Julios Armand Kontchou ◽  
Bernd Sures

Abstract Background In order to protect aquatic environments and to reduce the presence of micropollutants in the global water cycle, wastewater treatment plants (WWTPs) often implement an additional treatment step. One of the most effective measures is the use of powdered activated carbon (PAC) as an adsorbent for micropollutants. This method provides sufficient elimination rates for several micropollutants and has been successfully employed in many WWTPs. Despite this success, there might be a drawback as the retention of the PAC in the WWTP can be challenging and losses of micropollutant-loaded PAC into the aquatic environment may occur. Upon emission, micropollutant-loaded PAC is expected to settle to the benthic zone of receiving waters, where sediment-dwelling organisms may ingest these particles. Therefore, the present study investigated possible adverse effects of micropollutant-loaded PAC from a WWTP as compared to unloaded (native) and diclofenac-loaded PAC on the sediment-dwelling annelid Lumbriculus variegatus. Results Native PAC induced the strongest effects on growth (measured as biomass) and reproduction of the annelids. The corresponding medium effective concentrations (EC50) were 1.7 g/kg and 1.8 g/kg, respectively. Diclofenac-loaded PAC showed lower effects with an EC50 of 2.5 g/kg for growth and EC50 of 3.0 g/kg for reproduction. Although tested at the same concentrations, the micropollutant-loaded PAC from the WWTP did not lead to obvious negative effects on the endpoints investigated for L.variegatus and only a slight trend of a reduced growth was detected. Conclusion We did not detect harmful effects on L. variegatus caused by the presence of MP-loaded PAC from a WWTP which gives an auspicious perspective for PAC as an advanced treatment option.


2018 ◽  
Vol 25 (31) ◽  
pp. 31062-31070 ◽  
Author(s):  
Katheem Kiyasudeen ◽  
Mahamad Hakimi Ibrahim ◽  
Syahidah Akmal Muhammad ◽  
Sultan Ahmed Ismail ◽  
Fadzil Noor Gonawan ◽  
...  

2021 ◽  
Author(s):  
Edris Bazrafshan ◽  
Amin Allah Zarei ◽  
Leili Mohammadi ◽  
Muhammad Nadeem Zafar ◽  
Maryam Foroughi ◽  
...  

Abstract Tetracycline (TCy) belongs to PPCPs is such an widely used antibacterial drug, which is discharged from urban wastewater treatment plants or agricultural effluents. Due to low metabolism, poor absorption, overuse, and misuse, TCy is considered as threat to environmental and its removal from waste-water is vital. In this research, a novel ionic liquid modified magnetic activated carbon nanocomposite (IL@mAC) was synthesized, characterized, and the adsorption efficiency of IL@mAC for removal of TCy was investigated under different operational parameters of pH (3–11); dose of IL@mAC (0.01–0.1 g/50 mL); reaction time (30–240 min), and initial TCy concentration (50-1500 mg/L). The IL@mAC characterization was done using XRD, VSM, SEM-EDX, BET, and FTIR. Results of equilibrium experiment showed that the highest removal efficiency (~ 98%) was obtained using 0.06 g of IL@mAC in 135 min at pH 7 and temperature 303 K. Considering the correlation coefficients (R2) for different adsorption models, it can be deduced that adsorption of TCy onto IL@mAC is better followed by Langmuir (0.9977) in comparison to Freundlich (0.9412), and Temkin (0.9536) models. Furthermore, Langmuir adsorption capacity was observed to be 666.7 mg/g. The regeneration study showed that IL@mAC retained around 85% TCy adsorption efficiency after 6th cycle. Finally, the present study indicates that the IL@mAC is of a high applicability and has extremely high adsorbent capacity to remove TCy from water compared to most of other benchmark adsorbents reported in literature.


Author(s):  
Sharmin Akter ◽  
Ferdousi Sultana ◽  
Md. Rakibul Kabir ◽  
Partha Pratim Brahma ◽  
Atkeeya Tasneem ◽  
...  

Pharmaceutical industries in Bangladesh are considered as one major industrial as well as environmental pollution problems which discharge a significant amount of organic contaminants in the environment hence require advanced treatment technologies to decontaminate pharmaceutical wastewater. In the present investigation, areca nut husk treated activated carbon (ANHC) was used as an adsorbent to remove chemical oxygen demand (COD) from pharmaceutical effluent as well as a comparative adsorption efficiency with commercial activated carbon (CAC) was performed.  The batch experiments were carried out in a laboratory scale. The materials also evaluated for different adsorbent dosages and contact times. The experiment revealed a removal percentage up to 70% for ANHC and 90% for CAC for 3g of adsorbents in 180 min. The adsorption processes were satisfactorily described by pseudo-second-order (PSO) kinetic model which shows a better fitting with the maximum regression coefficient for both adsorbents. The results show that Langmuir model best described the experimental data with a highest correlation coefficient (R2=0.9856 for ANHC and 0.9993 for CAC) compared to Freundlich model and the experimental data showed asorption capacity of 36.549 and 64.935 mg/g for ANHC and CAC, correspondingly. According to the adsorption studies, the results revealed that COD adsorption process followed by the monolayer chemisorption mechanisms. The results revealed that ANHC adsorbent is potentially low cost and environmental friendly adsorbent for the removal of organic matter from pharmaceutical effluent.


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