Three different carbonaceous materials, activated carbon, graphene oxide, and multi-walled carbon nanotubes, were modified by nitric acid and used as adsorbents for the removal of methylene blue dye from aqueous solution. The adsorbents were characterized by N2 adsorption/desorption isotherms, infrared spectroscopy, particle size, and zeta potential measurements. Batch adsorption experiments were carried out to study the effect of solution pH and contact time on dye adsorption properties. The kinetic studies showed that the adsorption data followed a pseudo second-order kinetic model. The isotherm analysis indicated that the adsorption data can be represented by Langmuir isotherm model. The remarkably strong adsorption capacity normalized by the BET surface area of graphene oxide and carbon nanotubes can be attributed to π–π electron donor acceptor interaction and electrostatic attraction.

Comparative study of methylene blue dye adsorption onto activated carbon, graphene oxide, and carbon nanotubes

Hydrogen peroxide modification enhances the ability of biochar (hydrochar) produced from hydrothermal carbonization of peanut hull to remove aqueous heavy metals: Batch and column tests

Removal of pharmaceutical compounds by activated carbon prepared from agricultural by-product

Surface water pollution by pharmaceuticals and an alternative of removal by low-cost adsorbents: A review.

Capacitive deionization is an emerging technology for energy-efficient water desalination and has attracted more and more attention in recent years. The capacitive deionization technology is based on ion electrosorption at the surface of a pair of electrically charged electrodes, which are commonly composed of carbon materials. Among numerous electrode materials, graphene-based materials are outstanding, playing a vital role during the deionization process due to their intriguing features. After a brief introduction of the theory and instruments of capacitive deionization, we systematically summarize the current progress in graphene nanosheets, porous graphene, graphene-based composites, surface tuned graphene and its composites as electrodes for capacitive deionization. We also present our perspectives on the development of graphene-based electrodes for capacitive deionization.

Graphene-based materials for capacitive deionization

Surface modification of coconut-based activated carbon by liquid-phase oxidation and its effects on lead ion adsorption

Coconut-based activated carbons were modified with sodium dodecyl sulfate (SDS). The activated carbons, which were modified by different concentrations of SDS, were characterized by acid/base titrations, textural analysis (BET), atomic absorption spectrochemical analysis and Zeta potential measurements. The effects of SDS modification on Pb2+ absorption were studied further. The results indicate that after the modification of SDS, there are new functional groups on the surface of modified activated carbons and the number of functional group has changed remarkably, the total acidity decreases observably, but the total alkalinity increases dramatically. With the increase of surface load with SDS, the Pb2+ adsorption mass of activated carbons increases and the optimal pH for Pb2+ adsorption of the SDS modified activated carbons is 5. The experimental data are simulated better by Freundlich isotherm model for the modified activated carbons, and the experimental data are simulated better by Langmuir isotherm model for unmodified ones.

Surface modification of coconut-based activated carbon by SDS and its effects on Pb 2+ adsorption

Semiconductor silicon plays a significant role in the microelectronics industry In this paper, the effects of polishing pressure on electrochemical characteristics of silicon wafers during chemical mechanical polishing (CMP) were investigated by dc polarization and ac impedance techniques The results revealed that polishing pressure had a strong influence on the electrochemical behavior of silicon wafers Mechanical abrasion improved the removal of the passivating layer and enhanced the wafer oxidation rate The corrosion current density and the polishing rate increased sublinearly with applied pressure Also, the CMP process of silicon wafers can be considered a sequential formation causing film removal, which was confirmed by testing the change with electrochemical impedance spectroscopy

Effects of Polishing Pressure on Electrochemical Characteristics of Silicon Wafers during CMP

Semiconductor silicon plays a significant role in microelectronic industries. In this paper, the effects of H 2 O 2 concentration on electrochemical characteristics of silicon wafers during chemical mechanical polishing (CMP) as well as under static conditions were investigated by dc polarization and ac impedance techniques. The results revealed that H 2 O 2 concentration had a strong influence on the electrochemical behaviors of silicon wafers. The passivation strengthened with increasing H 2 O 2 concentration under the static condition. The addition of H 2 O 2 into the slurry increased the potential drop between static and polishing conditions, and the maximal potential drop was observed in the slurry with 1 vol % H 2 O 2 . There existed an optimal H 2 O 2 concentration to obtain the maximum corrosion current density and polishing rate. A low surface roughness could be obtained after CMP.

Effects of H2O2 on Electrochemical Characteristics of Silicon Wafers during Chemical Mechanical Polishing

Clostridium sp. LQ25 was cultured in different forms of ferric (ferric citrate and ferric hydroxide) as electron acceptors to investigate growth, ferric reduction, hydrogen production, fermentation products and fermentation process. The growth of the strain LQ25 detected by protein was 82.8 ± 2.1 mg/L and 73.5 ± 1.7 mg/L using ferric citrate and ferric hydroxide as electron acceptors, which was 33.3 % and 18.4 % higher than without ferric, respectively. The accumulation concentration of Fe(II) was 9.0 ± 0.6 mg/L and 5.0 ± 0.2 mg/L when using ferric citrate and ferric hydroxide as electron acceptors, and ferric citrate was 1.8-fold higher than ferric hydroxide, which indicated that the ability of ferric reduction was higher using ferric citrate as electron acceptor. The hydrogen production of strain LQ25 was 238.0 ± 1.0 mmol/mol glucose and 113.0 ± 1.3 mmol/mol glucose under condition of ferric citrate and ferric hydroxide as electron acceptors, which was 2.6 and 1.2-fold higher than without ferric, respectively. The growth and hydrogen production of strain LQ25 was promoted by using ferric as electron acceptor, while the fermentation type of strain did not change and was always butyrate type. The differential expression of the genes of strain LQ25 was significant when using ferric as electron acceptor, mainly in NADH and PFL pathway. This study provided preliminary evidence for hydrogen production by Clostridium sp. LQ25 in the presence of electron acceptor.

Hongyan Liu

Papers

Surface modification of coconut-based activated carbon by liquid-phase oxidation and its effects on lead ion adsorption

Surface modification of coconut-based activated carbon by SDS and its effects on Pb 2+ adsorption

Effects of Polishing Pressure on Electrochemical Characteristics of Silicon Wafers during CMP

Effects of H2O2 on Electrochemical Characteristics of Silicon Wafers during Chemical Mechanical Polishing

Renewable biohydrogen production from Clostridium sp. LQ25 using different forms of ferric as electron acceptor.