Facile preparation of porous biomass charcoal from peanut shell as adsorbent

Carbonized balsa wood-based photothermal evaporator for treating inorganic chemical wastewater

Solar desalination provides a sustainable and eco-friendly solution for purifying wastewater, addressing environmental challenges associated with wastewater treatment. This study focuses on the purification of inorganic contaminants from laboratory chemical wastewater (ICWW) using a spherical solar still (SSS). To enhance the evaporation rate and overcome the impact of heavy metals on absorption efficiency, a carbonized balsa wood (CBW) solar evaporator was employed. Balsa wood pieces, carbonized at 250 °C for 15 min, were arranged in a SSS configuration. The CBW-integrated SSS demonstrated a remarkable freshwater productivity of 2.33 L/m2 for ICWW, surpassing the conventional SSS, which produced only 1.5 L/m2. The presence of heavy metal ions (Na+, Ca+, K+, and Mg2+) in ICWW significantly affected the evaporation rate, and the CBW solar evaporator exhibited an impressive removal efficiency of approximately 99%. Water quality parameters, including pH and chemical oxygen demand (COD), were investigated before and after treatment. The CBW-integrated SSS achieved an outstanding COD removal efficiency of about 99.77%, reducing the COD level from 229.51 to 0.521 mg/L. These results underscore the efficacy of the proposed solar desalination system in purifying ICWW, offering a promising approach to address environmental concerns associated with wastewater treatment.

Flower-shaped Ni(OH)2decorated with biomass-derived carbon TPB-1 for asymmetric supercapacitors

In recent years, notable headway has been made in augmenting supercapacitor functioning through employment of pioneering components, exceptional nanostructures and additional investigation of electrolytes. Nonetheless, achieving superior performance with straightforward techniques remains a significant hurdle. In order to surmount this, an experimental three-dimensional nanospherical pore structure (TPB-20@Ni(OH)2) was designed and prepared. TPB-1 was obtained through carbonisation and activation. TPB-20@Ni(OH)2nanoparticles were synthesized using TPB-1 as the carbon source and nickel chloride hexahydrate as the nickel source. Furthermore, the TPB-20@Ni(OH)2//AC supercapacitor displayed an impressive energy density of 22.1 Wh kg-1. The TPB-20@Ni(OH)2composites exhibited a specific capacity of 978 F-1, which is noteworthy. The exceptional output exhibited by the TPB-20@Ni(OH)2composite derives from its innovative structure, presenting an extensive specific surface area of 237.4 m2g-1and porosity of roughly 4.0 nm. Following 20 000 cycles (at a current density of 1 A g-1), asymmetric supercapacitors assembled from TPB-20@Ni(OH)2//AC retained 80.0% of its initial specific electrostatic capacity, indicating superior electrochemical stability and high electrochemical reversibility.

Ba-modified peanut shell biochar (PSB): preparation and adsorption of Pb(II) from water

The impact of Ba-modified peanut shell biochar (Ba-PSB) on Pb(II) removal was studied and BaCl2 was used as a modifier. It was shown that the PSB obtained at 750 °C had the best adsorption effect, and the Ba-PSB had a larger specific surface area and a good adsorption effect on Pb(II). At pH = 5, concentration was 400 mg/L, time was 14 h, and temperature was 55 °C, the loading amount of black peanut shell biochar (BPSB), red peanut shell biochar (RPSB), Ba-BPSB, and Ba-RPSB reached 128.050, 98.217, 379.330, and 364.910 mg/g, respectively. In addition, based on the non-linear fitting, it was found that the quasi-second-order kinetic model, and isothermal model could be applied to describe Pb(II) adsorption on PSB and Ba-PSB. The adsorption behavior of PSB unmodified and modified was a spontaneous process. Moreover, chemical modification of BPSB, RPSB, Ba-BPSB, and Ba-RPSB for hindering of -COOH and -OH groups revealed 81.81, 77.08, 86.90, and 83.65% removal of Pb(II), respectively, which was due to the participation of -COOH, while 17.61, 21.70, 12.77, and 15.06% was from -OH group, respectively. The increase of cation strength (Na+, K+, Ca2+, and Mg2+) will reduce the adsorption capacity of PSB for Pb(II).

MoS2 nanobelts-carbon hybrid material for supercapacitor applications

The MoS2 nanobelts/Carbon hybrid nanostructure was synthesized by the simple hydrothermal method. The MoS2 nanobelts were distributed in the interlayers of Lemon grass-derived carbon (LG-C), provides the active sites and avoid restacking of the sheets. The structural and morphological characterization of MoS2/LG-C and LG-C were performed by Raman spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The electrochemical measurements were studied with cyclic voltammetry, the galvanostatic charge-discharge method, and electrochemical impedance spectroscopy. The specific capacitance of MoS2/LG-C and LG-C exhibits 77.5 F g-1 and 30.1 F g-1 at a current density of 0.5 A g-1. The MoS2/LG-C-based supercapacitor provided the maximum power density and energy density of 273.2 W kg-1 and 2.1 Wh kg-1, respectively. Furthermore, the cyclic stability of MoS2/LG-C was tested using charging-discharging up to 3,000 cycles, confirming only a 71.6% capacitance retention at a current density of 3 A g-1. The result showed that MoS2/LG-C is a superior low-cost electrode material that delivered a high electrochemical performance for the next generation of electrochemical energy storage.

Green preparation of graphene oxide nanosheets as adsorbent

As a basic building block of graphene-based materials, graphene oxide (GO) plays an important role in scientific research and industrial applications. At present, numerous methods have been employed to synthesize GO, there are still some issues that need to be solved, thus it is of importance to develop a green, safe and low-cost GO preparation method. Herein, a green, safe and fast method was designed to prepare GO, namely, graphite powder was firstly oxidized in a dilute sulfuric acid solution (H₂SO₄, 6 mol/L) with hydrogen peroxide (H₂O₂, 30 wt%) as oxidant, and then exfoliated to GO by ultrasonic treatment in water. In this process, H₂O₂ was the only oxidant, and no other oxidants were used, thus the explosive nature of GO preparation reaction in the conventional methods could be completely eliminated. This method has other advantages such as green, fast, low-cost and no Mn-based residues. The experimental results confirm that obtained GO with oxygen-containing groups has better adsorption property compared to the graphite powder. As adsorbent, GO can remove methylene blue (50 mg/L) and Cd²⁺ (56.2 mg/L) from water with removal capacity of 23.8 mg/g and 24.7 mg/g, respectively. It provides a green, fast and low-cost method to prepare GO for some applications such as adsorbent.

Preparation of Reusable Porous Carbon Nanofibers from Oxidized Coal Liquefaction Residue for Efficient Adsorption in Water Treatment

Porous carbon nanofibers are commonly used for adsorption processes owing to their high specific surface area and rich pore structure. However, the poor mechanical properties of polyacrylonitrile (PAN)-based porous carbon nanofibers have limited their applications. Herein, we introduced solid waste-derived oxidized coal liquefaction residue (OCLR) into PAN-based nanofibers to obtain activated reinforced porous carbon nanofibers (ARCNF) with enhanced mechanical properties and regeneration for efficient adsorption of organic dyes in wastewater. This study examined the effects of contact time, concentration, temperature, pH, and salinity on the adsorption capacity. The adsorption processes of the dyes in ARCNF are appropriately described by the pseudo-second-order kinetic model. The maximum adsorption capacity for malachite green (MG) on ARCNF is 2712.84 mg g^-1 according to the fitted parameters of the Langmuir model. Adsorption thermodynamics indicated that the adsorptions of the five dyes are spontaneous and endothermic processes. In addition, ARCNF have good regenerative performance, and the adsorption capacity of MG is still higher than 76% after 5 adsorption-desorption cycles. Our prepared ARCNF can efficiently adsorb organic dyes in wastewater, reducing the pollution to the environment and providing a new idea for solid waste recycling and water treatment.

Preparation of biomass-based gas separation membranes from biochar residue obtained by depolymerization of lignin with ZSM-5 to promote a circular bioeconomy

Reuse of biochar residues after lignin degradation will not only save costs but also reduce the pollution, protect and improve the environment. In this study, biochar residue (BR) after peanut shell lignin selective depolymerization on ZSM-5 were recycled, and characterized by Scanning Electron Microscopy, Surface area & pore size distribution analyzers, Thermogravimetric Analysis. Subsequently, a series of hybrid matrix membranes were prepared using ethyl cellulose as the matrix and biochar residue after depolymerization under different reaction conditions as the filler. The separation performance of BR/EC membranes for CO₂/CH₄ mixed gas and CO₂/N₂ mixed gas was measured. The results showed that the gas separation membranes prepared with biochar residue (3 h, 300 °C) as filler had good gas separation characteristics. The resulting mixed-matrix membrane exhibited a permeability of 66.00 Barrer for CO₂ and selectivities of 9.97 for CO₂/CH₄. Meanwhile, the resulting mixed-matrix membrane exhibited a permeability of 79.53 Barrer for CO₂ and selectivities of 20.01 for CO₂/N₂. Both exceed the upper limit of known pure EC membranes. Therefore, the use of biochar residue after ZSM-5 depolymerization as a filler for gas separation membranes is a feasible way. Furthermore, the membrane is well stabilized, proving its good potential for industrial applications.