Preparation and Adsorption Properties of Soybean Dreg/Hydrocalumite Composites

Calcined Bean Dregs-Hydrocalumite Composites as Efficient Adsorbents for the Removal of Ofloxacin

Calcined bean dregs-hydrocalumite composites were prepared through in situ self-assembly of hydrocalumite on the surface of bean dregs and used for the adsorption of ofloxacin from water. The adsorbents were characterized by scanning electron microscopy, X-ray powder diffraction, and N2 physical adsorption. The results showed that the adsorption performance of calcined bean dregs-hydrocalumite composites for ofloxacin was much better than that of a single bean dreg carbon or calcined hydrocalumite. The effects of preparation and adsorption conditions on the adsorption property of calcined bean dregs-hydrocalumite for ofloxacin were also investigated. The adsorption ratio of ofloxacin reached up to 99.93% using 4 g·L-1 adsorbent dosage with 20 mg·L-1 initial concentration of ofloxacin at 30 °C in 2 h. The adsorption process mainly occurred in the first 5 min. In addition, the adsorption of ofloxacin by calcined bean dregs-hydrocalumite was more in line with pseudo-second-order dynamics and the Langmuir isotherm model.

Efficient adsorption of Congo red by micro/nano MIL-88A (Fe, Al, Fe-Al)/chitosan composite sponge: Preparation, characterization, and adsorption mechanism

MIL-88A crystals with three different metal ligands (Fe, Al, FeAl) were prepared by hydrothermal method for the first time. The three materials' crystal structure and surface morphology are different, leading to different adsorption properties of Congo red (CR). The maximum adsorption capacities of MIL-88A (Fe), MIL-88A (FeAl), and MIL-88A (Al) are 607.7 mg · g^-1, 536.4 mg · g^-1, and 512.1 mg · g^-1 respectively. In addition, MIL-88A was combined with chitosan (CS) respectively, and MIL-88A/CS composite sponge was prepared by the freeze-drying method, which not only solved the defect that MIL-88A powder was difficult to recover but also further improved the removal ability of CR by the adsorbent. The maximum adsorption capacities of MIL-88A (FeAl)/CS, MIL-88A (Fe)/CS, MIL-88A (Al)/CS, and CS are 1312 mg · g^-1, 1056 mg · g^-1, 996.7 mg · g^-1, and 769.6 mg · g^-1, respectively. The structure and physicochemical properties of the materials were analyzed by SEM, FTIR, XRD, TGA, BET, and Zeta. The adsorption process of CR follows pseudo-second-order kinetics and Langmuir, Sips isotherm model. Combined with thermodynamic parameters, the adsorption behavior was described as endothermic monomolecular chemical adsorption. The removal of CR is attributed to electrostatic interactions, hydrogen bonding, metal coordination effects, and size-matching effects.

Preparation and Application of Foaming Agent Based on the Compound System of Short-Chain Fluorocarbon and Soybean Residue Protein

This study provides a new idea for the design of an advanced foaming agent with soybean residue protein (SRP) as a potential protein source. In order to achieve the most effective foaming performance, we employed the novel approach of response surface methodology (RSM) to improve important process parameters in a hot-alkali experiment. The experimental results showed that the optimum reaction parameters of pH and temperature were pH 10.2 and 50.5 °C, respectively, which, when continued for 3 h, led to the highest foaming property of the SRP foaming agent (486 mL). Based on the scheme, we also designed an experiment whereby we incorporated 1.0g/L FS-50 into the SRP foaming agent (SRP-50) to achieve higher foaming capacity compared with the commercial foaming agent. This foaming agent was cheaper than commercial vegetable protein foaming agents (12 USD/L) at 0.258 USD/L. Meanwhile, the properties of foam concrete prepared using SRP-50 were studied in comparison with a commercial vegetable protein foaming agent (PS). The results demonstrated that the foam prepared using SRP-50 had better stability, and the displacement of the foam decreased by 10% after 10 min. During the curing period, the foam concrete possesseda compressive strength of 5.72 MPa after 28 days, which was an increase from 2.95 MPa before. The aperture of the foam ranged from 100 to 500 μm with the percentage increasing up to 71.5%, which indicated narrower pore-size distribution and finer pore size. In addition, the shrinkage of the foam concrete was also improved. These findings not only achieve the utilization of waste but also provide a new source for protein foaming agents.

Effects of biochar amendment on bioconversion of soybean dregs by black soldier fly

Biochar is known to accelerate composting process and improve the quality of end-products. However, its effects on bioconversion of organic waste by black soldier fly larvae (BSFL) remains largely unexamined. To investigate the effects of corn straw biochar (CS-BC) on bioconversion of soybean dregs (SD) by BSFL, SD was amended with four different dosages of CS-BC [0%, 2%, 5%, and 8% (w/w)] and digested by BSFL for ten days. The results indicated that the peak values of single larva wet weight in the treatments amended with CS-BC were advanced by 2-3 days and the reduction rate of SD increased from 72.09% to 85.37% with the increasing dosage of CS-BC. Meanwhile, SD mixed with 2%, 5% and 8% of CS-BC decreased ammonia (NH3) emission by 2.7%, 3.6% and 18.0%, respectively. The nitrous oxide (N2O) emissions reduced (-23.6%, -29.1% and -49.2%) with 2%, 5% and 8% CS-BC additions, respectively. In addition, the residual nitrogen of SD‑nitrogen proportionally increased with CS-BC application (28.3%, 28.6%, 30.1% and 35.0% for application at the dosage of 0%, 2%, 5% and 8%, respectively). Based on the comprehensive evaluation of bioconversion performance, alleviation of pollutant gas emission, and nitrogen conservation, we recommend the introduction of 8% (w/w) CS-BC during bioconversion of SD by BSFL. This study confirmed the feasibility of CS-BC as an amendment for the BSFL-based bioconversion system.

Bean Dreg-Hydrocalumite Composite as a Highly Efficient Thermal Stabilizer for Poly(vinyl chloride)

Bean dreg (BD)-hydrocalumite composites were prepared by a hydrothermal method with BD, Ca(OH)₂, Al(OH)₃, and Na₂CO₃ as raw materials. The samples were characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and N₂ physical adsorption-desorption. Their properties as a thermal stabilizer for poly(vinyl chloride) were tested using a torque rheometer and static thermal aging method. Compared with traditional hydrocalumite, the crystal size of the BD-hydrocalumite composite was relatively small, which made it exhibit good dispersion and better thermal stability for poly(vinyl chloride). In addition, the effects of preparation conditions on the properties of BD-hydrocalumite as a heat stabilizer were also investigated. Under the conditions of n[Ca(OH)₂/Al(OH)₃/Na₂CO₃] = 4.4:2:1, a BD dosage of 5%, a crystallization temperature of 90 °C, and 19 h, the prepared BD-hydrocalumite showed the best performance, and the dynamic thermal stability time of poly(vinyl chloride) reached 2149 s.