废弃烟梗发酵生产真菌吸附剂及其脱色作用

为资源化利用废弃烟梗,从其固态发酵物中分离筛选出1株对染料有高效吸附脱色作用的真菌,根据培养和显微特征初步鉴定为青霉菌(Penicilliumsp.),命名为LY7。LY7能够在废弃烟梗水提取液中快速生长形成菌丝球。以刚果红为目标染料,研究了青霉菌LY7灭活菌丝球和由菌丝球制备的粉状菌体生物吸附剂的脱色效果,结果表明:在振荡脱色条件下,8 g/L的灭活菌丝球3 h对100 mg/L的刚果红溶液的脱色率为96.4%;1.5 g/L的粉状菌体对100 mg/L刚果红溶液9 h的脱色率为95.4%。因此,利用废弃烟梗水提取物发酵生产青霉LY7菌体制备生物吸附剂,既能应用于染料废水脱色,又能为废弃烟梗的资源化利用提供一种新思路。     

Biosorption of Heavy Metals by Powder of Green Coconut Shell

Abstract

Alternative processing methods are being considered more seriously, sorption and/or complexation of dissolved metals based on the chemical activity of biomass, known as biosorption, is the base of the new technology for metal removal and recovery. Different types of biomass (dead and alive) like bacteria, yeast, bark, fungi, agricultural by‐products, coconut shell, marine algae, peat, moss and aquatic mosses have been investigated for biosorption of heavy metals ions. Biosorption of each of the metal ions by coconut shell powder was investigated in this study. The biosorption capacities of coconut shell for cadmium, chromium, and arsenic were studied at different particle sizes (0.044–0.297 mm), initial metal concentration (20– 1000 mg/L), and solution pH values 2–9 Churchill, S. A., Walters, J. V. and Churchill, P. F. 1995. Sorption of heavy metals by prepared bacterial cell surface. J. Environ. Eng., 121(10): 706–711. Kuyucak, N. and Volesky, B. 1988. Biosorbents for recovery of metals from industrial solutions. Biotechnol. Lett., 10(2): 137–142. Espósito, A., Pagnanelli, F., Lodi, A., Solisio, C. and Veglio, F. 2001. Biosorption of heavy metals by Sphaerotilus natans: an equilibrium study at different pH and biomass concentration. Hydrometallurgy, 60: 129–141. Pino, G. A.H. 2005. “Biosorption of heavy metals using powder of green coconut shell”. Brazil: Master's Thesis, Catholic University of Rio de Janeiro. (In Portuguese) Chandra, K., Kamala, C. T., Chary, N. S. and Anjaneyulu, Y. 2003. Removal of heavy metals using a plant biomass with reference to environmental control. International Journal of Mineral Processing, 68: 37–45. Dornellas de Barros, M. A. 2000. Remoção de metais em água utilizando diversos adsorventes. Revista Tecnológica, : 65–72. Ed especial Gaballah, I., Goy, D., Kilbertus, G. and Thauront, J. 1994a. Decontamination of industrial effluents for environment protection and recycling of metals. Resources, Conservation and Recycling, 10: 97–106. Schneider, I., Rubio, J. and Smith, R. 2001. Biosorption of metals onto plant biomass: exchange adsorption or surface precipitation?. International Journal of Mineral Processing, 62: 111–120.   in batch mode, the experimental data obtained for each metal were evaluated and fitted using adsorption models. Also, analyses were made of biomass by SEM‐EDS before and after the biosorption to confirm the presence of metal ions species.     

Removal of cesium from radioactive wastewater using magnetic chitosan beads cross-linked with glutaraldehyde

A novel magnetic chitosan bead cross-linked with glutaraldehyde was prepared, characterized and applied for Cs(I) removal from aqueous solution. Characteristics and mechanism of Cs(I) removal were investigated. The equilibrium data of Cs(I) adsorption by magnetic chitosan beads were fitted using the Langmuir,Freundlich, Tempkin, Redlich–Peterson(R–P), Slips and Dubini–Radushkevich(D–R) models. The maximum adsorption capacity was estimated at 3.86 mg/g from the Langmuir isotherm. FTIR study revealed that N atom was mainly involved in Cs(I) sorption by magnetic chitosan.The magnetic chitosan is a promising adsorbing material for treating Cs(I)-containing radioactive wastewater.     

Use of rice straw as biosorbent for removal of Cu(II), Zn(II), Cd(II) and Hg(II) ions in industrial effluents

Adsorption experiments were carried out using waste rice straw of several kinds as a biosorbent to adsorb Cu(II), Zn(II), Cd(II) and Hg(II) ions from aqueous solutions at room temperature. To achieve the best adsorption conditions the influence of pH and contact time were investigated. The isotherms of adsorption were fitted to the Freundlich equation. Based on the experimental data and Freundlich model, the adsorption order was Cd(II) > Cu(II) > Zn(II) > Hg(II) on the rice straw. This quick adsorption process reached the equilibrium before 1.5 h, with maximum adsorptions at pH 5.0. Thermodynamic aspects of the adsorption process were investigated. The biosorbent material was used in columns for the removal of ions Cu, Zn, Cd and Hg of real samples of industrial effluent and its efficiency was studied.     

A novel biosorbent for dye removal: extracellular polymeric substance (EPS) of Proteus mirabilis TJ-1

This paper deals with the extracellular polymeric substance (EPS) of Proteus mirabilis TJ-1 used as a novel biosorbent to remove dye from aqueous solution in batch systems. As a widely used and hazardous dye, basic blue 54 (BB54) was chosen as the model dye to examine the adsorption performance of the EPS. The effects of pH, initial dye concentration, contact time and temperature on the sorption of BB54 to the EPS were examined. At various initial dye concentrations (50-400 mg/L), the batch sorption equilibrium can be obtained in only 5 min. Kinetic studies suggested that the sorption followed the internal transport mechanism. According to the Langmuir model, the maximum BB54 uptake of 2.005 g/g was obtained. Chemical analysis of the EPS indicated the presence of protein (30.9%, w/w) and acid polysaccharide (63.1%, w/w). Scanning electron microscopy (SEM) images showed that the EPS with a crystal-linear structure was whole enwrapped by adsorbed dye molecules. FTIR spectrum result revealed the presence of adsorbing groups such as carboxyl, hydroxyl and amino groups in the EPS. High-molecular weight of the EPS with more binding-sites and stronger van der Waals forces together with its specific construct leads to the excellent performance of dye adsorption. The EPS shows potential board application as a biosorbent for both environmental protection and dye recovery.     

Utilisation of chitinous materials in pigment adsorption

The effect of adding the cells of four lactobacilli to a squid pen powder (SPP)-containing medium on prodigiosin (PG) production by Serratia marcescens TKU011 is examined. The best increase in PG productivity was shown by strain TKU012. Among the samples of strain TKU012 and the chitinous materials of cicada casting powder (CCP), shrimp shell powder (SSP), squid pen powder (SPP), α-chitin, and β-chitin, TKU012 cells displayed the best adsorption rate (84%) for PG, followed by CCP, SSP, SPP, α-chitin, and β-chitin. As for the water-soluble food colourants, Allura Red AC (R40) and Tartrazne (Y4), SPP and SSP had better adsorptive powers than pure chitin preparations, strain TKU012, and CCP. Treatment with organic solvents, hot alkali, or proteases (papain, bromelain) diminished the adsorption rates of the biosorbents.     

The CO2 adsorptive and regenerative behaviors of Rhizopus oligosporus and carbonaceous Hibiscus cannabinus exposed to thermal swings

Rhizopus oligosporus and carbonaceous Hibiscus cannabinus L. were artificially converted into active bio-sorbents to study their CO₂ adsorptive and regenerative capacities under thermal fluctuations. A naturally dried Tempe (soybean slab) demonstrated CO₂ adsorption of 0.10 mol/g in the first cycle, while, carbonaceous Tempe comprising 54.69% of carbon content demonstrated CO₂ adsorption of 0.06 mol/g. The relatively higher adsorption by the dried Tempe was attributed to the presence of active R. oligosporus micro-sites. Despite lower affinity, carbonaceous Tempe was superior in term of its thermal durability and adsorption consistency. Carbonaceous Kenaf (H. cannabinus L.) with ZnCl₂ promoter at a ratio of 3:5, comprising 63.29% of active carbon content, demonstrated the highest CO₂ adsorption of 17.39 mol/g in the 56 min run, hundreds folds higher than that demonstrated by the dried Tempe. The carbonaceous Kenaf, also found to be highly resilient against repeated heating, however, exhibited rather meager regenerative capability compared to the sample containing smaller amount of zinc chlorides.     

Preparation and application of iron oxide/persimmon tannin/ graphene oxide nanocomposites for efficient adsorption of erbium from aqueous solution

Rare earth elements (REEs) are used for the development of new energy materials owing to their intrinsic physicochemical property. However, excess REEs in water threaten the safety of animals, plants and humans. An efficient way to separate REEs from the water is therefore needed. In this study, a biosorbent consisting of iron oxide (Fe₃O₄), persimmon tannin (PT), and graphene oxide (GO) as Fe₃O₄/PT/GO was prepared, and the adsorption of trivalent erbium (Er³⁺) ions from aqueous solution was investigated. The adsorption process for Er³⁺ ions conforms to pseudo-second order kinetic and the Langmuir isotherm model behavior. Thermodynamic studies indicate that the adsorption process is spontaneous and endothermic. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy, Brunauer-Emmett-Teller (BET) analysis, and vibrating sample magnetometer (VSM) were used to assess the adsorption mechanism of Er³⁺ ions onto the Fe₃O₄/PT/GO biosorbent. A combination of electrostatic interactions, redox reactivity and chelation are responsible for adsorption of Er³⁺ ions on the Fe₃O₄/PT/GO biosorbent. The magnetic Fe₃O₄/PT/GO biosorbent can be easily separated under the magnetic field for effective recycle of Er³⁺ ions from aqueous solution. Therefore, this new biomass composite holds great promise for wastewater treatment.     

Bio-sorption of atrazine in the press-cake from oilseeds

Oilseed press-cake (PC) is proposed as a novel material for the removal of hydrophobic organic pollutants (HOPs) from water. Sorption of the pesticides carbaryl, atrazine and parathion, with log K(ow) being, respectively, 1.59, 2.55 and 3.83, was demonstrated using cold-pressed rapeseed (Brassica napus), moringa (Moringa oleifera) and soybean (Glycine max) PCs. Linear sorption isotherms have been observed. The partition coefficient of carbaryl, atrazine and parathion using rapeseed PC were determined to be 0.028+/-0.003, 0.144+/-0.003 and 2.52+/-0.24 L/g, respectively. Partition studies of atrazine in PC-extracted oil and defatted PC showed that the sorption mechanism is mainly through absorption in the residual oil in the PC, whereas adsorption on the PC matrix is quantitatively much less significant. It was also shown that the oil content of the PC is not the only parameter determining the partitioning of pesticides. Indeed, sorption using ground seeds was very weak, as demonstrated by the low partition and mass transfer coefficients. This may be due to cell structures blocking the pesticide diffusion to the oil-containing structures within the seeds, while for PC oil they are present in the form of small (10 microm) droplets trapped within the hydrophilic PC matrix, thus presenting less resistance for mass transfer.     

Optimization of process variables for a biosorption of nickel(II) using response surface method

The biosorption of nickel(II) was studied by using crab shell particles of diameter (d _p =0.012 mm) under different initial concentrations of nickel(II) in solution (0.01–5.0 g/l), temperature (20–40 °C), pH (2–6.5), and biosorbent dosages (0.5–10 g/l). The maximum removal of nickel(II) occurred at pH 6.5 and temperature 40 °C for a biosorbent dosage of 6 g/l. The results were modeled by response surface methodology (RSM), which determines the maximum biosorption of nickel(II) as a function of the above four independent variables, and the optimum values for the efficient biosorption of nickel(II) were obtained. The RSM studies were carried out using Box-Behnken design and the analysis of variance confirms the adequacy of the quadratic model with coefficient of correlation R² to be 0.9999. The quadratic model fitted the data well with Prob>F to be <0.0001, indicating the applicability of the present proposed model.