Adsorption Science & Technology

Thirteen carbon materials were tested as sorbent layers in bar adsorbent microextraction (BAμE) to monitor hint amounts of 10 common pharmaceutical compounds (PhCs) in surface and groundwater matrices such as surface and groundwater, saltwater, spring water, and sewage. The persistence of trace amounts of three organophosphate insect repellent and cis and trans permethrin (PERM) in water quality matrices is suggested using bar adsorptive microextraction in conjunction with microliquid dissolution accompanied by significant volume injection-gas chromatography-mass spectroscopic analysis able to operate in the particular ion monitoring acquisition mode. Using BAμE to compare several sorbent coatings (five porous carbon and six polymers), it was discovered that activated carbon (AC2) was the optimum compromise among specificity and effectiveness. 17-estradiol, estrone, sulfamethoxazole, diclofenac, triclosan, gemfibrozil, 17-ethinylestradiol, mefenamic acid, and clofibric acid were chosen as system drugs to represent different treatment groups. Despite their lower porosity, statistics revealed that low-T-activated hydrochars, made from carbohydrates and a eutectic salt mixture at constant temperature (e.g., 180°C) and autogenerated pressures, could compete at the top level commercially carbonaceous materials in this purpose. These L-T-activated hydrochars had the best overall recovery (between 21.8 and 83.5 percent) for the simultaneous analysis of ten targeted PhCs with very different physical and chemical possessions, utilizing higher-efficiency liquid chromatography diode array identification.

Magnetic Mg_xCo_yZn_(1-x-y)Fe₂O₄ nanoparticles were successfully prepared by the rapid combustion approach, and SEM, XRD, VSM, EDX, and FTIR techniques were applied for their characterization. The influence of the element ratios (Mg²⁺, Co²⁺, and Zn²⁺) in magnetic Mg_xCo_yZn_(1-x-y)Fe₂O₄ nanoparticles on their properties was explored. To acquire a larger specific surface area for better adsorption of methyl blue (MB), magnetic Mg_0.4Co_0.5Zn_0.1Fe₂O₄ nanoparticles calcined at 400°C for 2 h with 25 mL anhydrous ethanol were selected, and their average particle size and the saturation magnetization were about 81.3 nm and 13.5 emu·g^-1, respectively. Adsorption kinetics models and adsorption isotherm models were applied to research the adsorption characteristics of MB onto magnetic Mg_0.4Co_0.5Zn_0.1Fe₂O₄ nanoparticles. The pseudo-second-order kinetics model () and Temkin isotherm model () were the most consistent with the data, indicating that the adsorption was the chemical multilayer adsorption mechanism, and the process was an exothermic reaction. The E of the Dubinin-Radushkevich (D-R) isotherm model was 0.2347 KJ·mol^-1, indicating the adsorption involved physical adsorption besides chemical adsorption. The and ( KJ·mol^-1) of the adsorption process of MB adsorbed onto magnetic Mg_0.4Co_0.5Zn_0.1Fe₂O₄ nanoparticles measured through the thermodynamic experiment were both less than 0, which proved that the process was a spontaneous exothermic reaction. The adsorption capacity of MB onto magnetic Mg_0.4Co_0.5Zn_0.1Fe₂O₄ nanoparticles increased with the pH of MB solution increasing from 2 to 4 at room temperature, and it had no significant change when the pH of MB solution was 4-12, while the relative removal rate was 98.75% of the first one after 2 cycles. The electrochemical impedance spectroscopy (EIS) and the cyclic voltammetry (CV) data further demonstrated that MB was adsorbed onto magnetic Mg_0.4Co_0.5Zn_0.1Fe₂O₄ nanoparticles.

Hazardous heavy metal ions such as copper, zinc, nickel, chromium, cadmium, and lead engender a potential risk to human health. Among the processes involved in the retention of these contaminants, adsorption is advantageous for removing toxic metals because of its environmentally friendly aspect, efficiency, and low-cost operation. Information on the adsorption of heavy metals in soils from the semiarid region of northeastern Brazil is still scarce. In this study, the adsorption of heavy metals (Cd, Cu, Zn, Ni, and Pb) by a semiarid Brazilian bentonitic soil is investigated. This soil has been used as a bottom liner in an experimental municipal solid waste (MSW) cell located in Campina Grande, State of Paraíba, Brazil. The experimental cell consists of a landfill unit on an experimental scale, with the same constructive elements of a sanitary landfill. Disturbed and undisturbed samples of the investigated soil were collected at a quarry in the rural zone of Boa Vista (state of Paraiba, Northeast Brazil). Sorption attributes were determined via batch tests with a soil-solution ratio of 1 : 12.5 (4 g of dry soil to 50 mL of solution). Linear, Freundlich, and Langmuir isotherms were fitted to the experimental data, using as fitting parameters Pearson correlation coefficient () and value with a significance level . The ascending order of maximum adsorption capacity for heavy metals followed the series Ni < Cr < Zn < Cd < Cu < Pb. The maximum adsorbent capacities obtained were similar to those of other Brazilian soils and other adsorbents. Therefore, the studied soil has a high potential to be used in the retention of heavy metals.

With significant benefits over many other commercialised thermal storage methods, activated carbon fiber (ACF) is believed to be among the finest biosorbents for adsorbent purposes. If correctly made, it is an outstanding mesoporous lightweight material with micropores and, in most cases, no micropores. ACF’s higher bulk densities and great dynamic capacity demonstrate its value and are used in adsorbent technologies. The present study’s primary goal is to create active carbon fiber from organic hemp fiber. The following parameters were selected: (i) activating temperatures, (ii) activating timing, (iii) carbonization temperature, (iv) activating ingredient %ages, and (v) speed of activation temperature, all with four levels to achieve the goal. Taguchi optimization techniques were used to optimize the adsorbent characteristics. The current study used an L16 orthogonal array to accomplish that improvement. According to the previous Taguchi, the optimal conditions were 300°C combustions, insemination with 22.5% K₂HPO₄ solution, and activating at 800°C for 3 hours at 20°C/min. The greatest contribution is 54.75%, followed by the rate of temperature activation at 23.35%, carbonated temperature at 10.14%, duration of stimulation at 8.82%, and H₃PO₄ concentrations at 2.94%. The results show that the activation temperature and rate of the temperature of activations are the essential elements in the current study’s accomplishment of the best adsorption capacities.

A new magnetic adsorbent, namely, MnFe₂O₄/D201, with deep-treatment ability and high selectivity adsorption for As(V) was prepared. According to isotherm adsorption and kinetics, As(V) adsorption is primarily used for chemical bonding throughout the single-layer adsorbing process. The maximum As(V) adsorption capacity of MnFe₂O₄/D201 can reach 35.8 mg/g at pH 3. MnFe₂O₄/D201 also exhibits higher selectivity adsorption against Cl^-, NO₃^-, SO₄^2-, and PO₄^3-. According to the thermodynamic results, the adsorption process was spontaneous and endothermic. The adsorption capacity is maintained at 81% of the initial after ten adsorption-desorption cycles. As(V) concentrations ranging from 1 mg/L to 10 μg/L can be treated in fixed-bed column experiments. The effectual cure volume of As(V) reaches 1332 BV (26.64 L). The removal mechanism primarily comprises electrostatic attraction and complexation.

Thermoplastic-based polymers are gathering importance in several engineering fields like electrical, electronic, automotive, aerospace, and structural. The additions of secondary phase reinforcements such as natural and synthetic fibre improve thermoplastic-based polymer’s properties. The thermoplastic and natural fibre combinations are found to have low mechanical strength and incompatibility and need special treatment for synthesizing the natural fibre. The present experimental investigation deals with the enhancement of polypropylene hybrid composite by using the combinations of glass (synthetic)/hemp (natural) fibre for the ratio of 0 : 35, 5 : 30, 10 : 25, and 15 : 20 reinforced with 5 wt% compatibilizer through injection moulding. The revealed test results of polypropylene hybrid composite showed improved mechanical impact and flexural and tensile strength of 37.5%, 14.2%, and 21.1%, respectively. The thermal adsorption characteristics were evaluated by thermogravimetric analysis apparatus. It showed the decomposition of composite limited by hemp fibre at 27°C to 700°C.