Adsorption Science & Technology

Nanozero-valent iron (NZVI) shows great potential in the remediation of water pollution, but its application is limited by its instability and tendency to aggregate. To enhance the dispersibility and antioxidant properties of NZVI, we prepared composites (SN) by wrapping NZVI with sodium alginate (SA) for the removal of Pb(II) from water. Various characterization methods such as SEM-EDS, BET, XPS, and FT-IR were used to study the structure of the materials, and the adsorption properties of Pb(II) in the materials were analyzed using adsorption kinetics and adsorption isotherm experiments. The results showed that SN had a specific surface area of 47.05 m²/g, which was significantly higher than the 7.56 m²/g of NZVI, and the surface passivation was reduced. The maximum adsorption amount of SN on Pb(II) was obtained by fitting the adsorption isotherm model at 70.92 mg/g. After five cycles of adsorption, SN exhibited a removal rate of 95.11% for Pb(II). The mechanism of Pb(II) removal by SN involved the synergistic effect of electrostatic adsorption, redox reaction, ion exchange, and coprecipitation. Notably, even after 90 days of aging, the removal rate of Pb(II) by SN remained high at 95.39%, demonstrating good reactivity. These results indicated that SN is an effective adsorbent to remove Pb(II) contamination.

In the present investigation, zinc oxide nanorods (ZnO-NR) were synthesized via the hydrothermal method using ZnCl₂ as a zinc ion precursor in the presence of cetyltrimethylammonium bromide. Synthesized ZnO-NR was featured using advanced techniques including XRD, PL, SEM, and UV-visible spectroscopy. The role of these assynthesized ZnO-NR was evaluated for the sequestration of lead ions in batch mode. The elimination of lead ions was achieved at pH 6-7 using a 0.06 g adsorbent dose, 25 min contact time, 25 mg/L initial lead ion concentration, 323 K temperature, and 200 rpm agitation speed. A thermodynamic study revealed the endothermic nature of lead ion sequestration onto ZnO-NR. The lead ion sequestration followed kinetic (pseudo-second-order) and isotherm (Langmuir) models. The lead ions were eliminated up to 142 mg/g at the optimum level of affecting variables. The ZnO-NR might be a potential adsorbent for lead ion removal from industrial effluents.

The efficiency of the grape stalk as a biosorbent for the malachite green removal from natural waters and industrial effluents was investigated in this work. For the optimization of experimental variables, a central composite design was used, in which the effect of pH and biosorbent dose was evaluated on biosorption capacity and removal percentage. Optimal parameters of pH 5 and biosorbent dose of 0.80 g L^-1 allowed a malachite green removal percentage of 87.7%. Data obtained from kinetic studies were fitted with the pseudo-second-order model. The maximum biosorption capacity was determined using the Langmuir equilibrium model, reaching a value of 214.2 mg g^-1. The biosorption process was thermodynamically favorable and spontaneous at room temperature. The calculated value of biosorption enthalpy change indicated that the nature of the process was exothermic and physical. The biosorption process was applied in natural waters and industrial effluent samples, obtaining removal percentages up to 84.3%, which demonstrates the efficiency of grape stalks for the treatment of complex matrices.

Due to the excessive use of paracetamol (PCM), a significant amount of its metabolite has been released into the surroundings, and its removal from the surroundings must happen quickly and sustainably. Multicomponent adsorption modelling is difficult because it is challenging to anticipate the relationships among the adsorbates in this artificial intelligence-based modelling, a choice among different algorithms. Utilizing various algorithms, many studies assessed the single and binary adsorption of paracetamol on activated carbon. The present study implements that the effectiveness of PCM adsorption on a carbon-activated nanomaterial was predicted using an artificial neural network, a machine learning technology. As a factor of adsorbent particle size, adsorbent dosage, training time, and starting concentrations, the adsorption capacity for each medicinal ingredient was examined. SEM was used to analyze a nanomaterial that had been chemically altered with orthophosphoric acid (FTIR). To determine the residual proportion of PCM in solvent, batch adsorption of PCM was then carried out at various operation conditions, including contact time, temperatures, and initial dosage. The adsorption effectiveness of paracetamol on carbon-activated nanoparticle was calculated using experimental results. Thus, by using machine learning framework, the adsorption efficiency of paracetamol on a carbon-activated nanomaterial was predicted.

Heterojunctions have proven to be effective catalysts for removing organic pollutants and heavy metals from wastewater. The following study is also about the formation of 2D heterojunction tellurium-doped zinc oxide composite with sulfur-doped graphitic carbon nitride ([email protected]₃N₄) by adopting a low-cost, simple, and ecofriendly coprecipitation technique. Thiourea was calcined to prepare S-g-C₃N₄ using the thermal degradation method. The characterization of synthesized photocatalysts was carried out by using SEM-EDX, FTIR, and XRD. The results obtained showed that the incorporation of tellurium caused an alteration in the wurtzite structure of ZnO. SEM-EDX analysis validated the purity of the synthesized samples due to the absence of any additional peaks. The decrease in the bandgap was also noted by the formation of composites. Using methylene blue as a reference dye, the UV-vis spectrophotometer was utilized to calculate the absorbance for photocatalytic degradation behavior. As a result of tellurium doping into the ZnO lattice, photocatalytic oxidation/reduction was improved, according to the results. 3Te-ZnO NPs showed the best degradation rate among dopant series, while an excellent overall degradation rate was noted by fabricated composite [email protected]₃N₄. The best doped ZnO and composites were also used as sorbents for the abstraction of heavy metal (Cr(VI)) from water via adsorption. A definite rise in the removal efficiency percentage of chromium ions was observed by using these sorbents. The overall photo degradation rate and adsorption behavior noted were in ZnO<Te-ZnO<[email protected]₃N₄ order. When compared to ZnO, Te-ZnO, SCN, and [email protected], the [email protected] NCs have outstanding antifungal potential. The improved dispersibility and interaction of [email protected] with membrane and intracellular proteins of fungi may be the cause of the greater effect of [email protected]

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.