Highly efficient recovery of phosphate and fluoride from phosphogypsum leachate: Selective precipitation and adsorption.

Phosphogypsum, a typical by-product in the phosphorus chemical industry, could generate a large amount of leachate containing phosphate and fluoride in the process of rainfall and long-term stacking, which not only causes serious environmental pollution, but also leads to a waste of resources. In this study, a united treatment of calcium hydroxide precipitation and lanthanum zeolite (La-ZFA) adsorption was proposed to achieve the recovery of phosphate and fluoride from phosphogypsum leachate. In phosphogypsum, most phosphorus could be leached except P in the residual occurrence form, while for fluoride, only water-soluble F could be effectively leached.

PPh/I Promoted Synthesis of Unsymmetrical Disulfides from Sodium Sulfites and 2-Mercaptobenzo Heterocyclics.

A simple and efficient method for the synthesis of unsymmetrical disulfides is reported. Using sodium sulfites and 2-mercaptobenzo heterocyclic compounds as starting materials, the unsymmetrical sulfur-sulfur bonds could be quickly constructed in the PPh/I reaction system under transition-metal-free conditions. This protocol has the advantages of mild reaction conditions, easily available starting materials, and wide substrate scope, showing potential synthetic value for the synthesis of a diversity of biologically or pharmaceutically active compounds.

Polyaminophosphoric Acid-Modified Ion-Imprinted Chitosan Aerogel with Enhanced Antimicrobial Activity for Selective La(III) Recovery and Oil/Water Separation.

In this study, polyaminophosphoric acid (PA)-functionalized ion-imprinted chitosan (CS) aerogel was fabricated for the first time, exhibiting good antibacterial property for selective La(III) recovery and oil/water separation. The as-prepared PA-CS-IIA-2 shows a remarkable adsorption capacity of 114.6 mg/g toward La(III) and high selectivity in the competitive adsorption systems, which is attributed to its abundant imprinting sites and surface functional groups.

Selective capture of Pd(II) from aqueous media by ion-imprinted dendritic mesoporous silica nanoparticles and re-utilization of the spent adsorbent for Suzuki reaction in water.

The development of highly efficient adsorptive material for the selective capture of Pd(II), and re-utilization of spent Pd(II)-loaded adsorbent as an efficient catalyst for organic synthesis are of great significance, but challenging. Particularly, the heterogeneous palladium-catalyzed Suzuki reaction in aqueous media is much more challenging than that of homogeneous. Herein, several novel Pd(II) ion-imprinted polymers (PIIPs) based on dendritic fibrous silica particles are constructed by surface ion imprinting technology (SIIT), using Schiff base and pyridine groups functionalized organosilicon as functional monomer.

Synthesis of rice husk-based ion-imprinted polymer for selective capturing Cu(II) from aqueous solution and re-use of its waste material in Glaser coupling reaction.

With the deepening of the concept of recycling economy and green chemistry, selective capture of Cu(II) from wastewater by biosorbent and reuse of the spent Cu(II)-loaded adsorbent are of great significance. Herein, we synthesized composite of rice husk (RH) with mesoporous silica MCM-41 (RH@MCM-41) modified by organosilane containing amino and schiff groups as functional monomer and cross-linking agent. The silica modified RH@MCM-41 was employed as supporter to fabricate copper ion-imprinted polymers as absorbents (named as RM-CIIPs) via surface ion imprinting technique.

Decorating UiO-66-NH crystals on recyclable fiber bearing polyamine and amidoxime bifunctional groups via cross-linking method with good stability for highly efficient capture of U(VI) from aqueous solution.

Although polyacrylonitrile fiber (PANF) and metal-organic frameworks (MOFs) have been extensively investigated to remove U(VI) from water, their practical applications are seriously hindered by the relatively low stability of PANF in acidic solution and great difficulty of separating MOFs nanoparticles from solution, beside that, little attention is paid to the fabrication of MOFs and PANF composite materials (MPCMs) with excellent adsorption capacity for U(VI). Herein, we report the synthesis of novel MPCMs by decorating different concentrations of UiO-66-NH2 crystals onto polyamine and amidoxime groups functionalized PANF (PA-AO-PANF) through cross-linking method for U(VI) extraction. The characterization results reveal that the combination of PA-AO-PANF and UiO-66-NH2 crystals endows MPCMs with excellent separation ability, large surface area, good stability and plentiful surface functional groups, which contributes to good selectivity and enhanced adsorption performance.

Simultaneous removal of cationic and anionic dyes from aqueous solution by double functional groups modified bagasse.

Double functional groups modified bagasse (DFMBs), a series of new zwitterionic groups of carboxyl and amine modified adsorbents, were prepared through grafting tetraethylenepentamine (TEPA) onto the pyromellitic dianhydride (PMDA) modified bagasse using the DCC/DMAP method. DFMBs' ability to simultaneously remove basic magenta (BM, cationic dye) and Congo red (CR, anionic dye) from aqueous solution in single and binary dye systems was investigated. FTIR spectra and Zeta potential analysis results showed that PMDA and TEPA were successfully grafted onto the surface of bagasse, and the ratio of the amount of carboxyl groups and amine groups was controlled by the addition of a dosage of TEPA.

Selective removal of phosphate from aqueous solution by MIL-101(Fe)/bagasse composite prepared through bagasse size control.

MIL-101(Fe)/sugarcane bagasse (SCB) with high adsorption capacity and selectivity toward phosphate was prepared through in-situ synthesis method. Effects of bagasse size on the morphology and performances of the composites were investigated, and adsorption behavior and mechanism of phosphate on the composite prepared at the optimum bagasse size were studied. Results showed that composite prepared with bagasse size of 200-300 mesh (MIL-101(Fe)/SCB) showed much higher adsorption capacity than SCB, blank MIL-101(Fe) and the composites prepared with the other bagasse size, which was due to the more positively charged surface and the more exposed adsorption active sites including FeOH and exchangeable Cl.

Effects of surface modification on heavy metal adsorption performance and stability of peanut shell and its extracts of cellulose, lignin, and hemicellulose.

Effects of surface modification by carboxyl group on Pb adsorption performances and stability of peanut shell and its extracts (cellulose, lignin, and hemicellulose) were investigated. Stability of the biosorbents was measured by determining organic compound release amount (TOC). Results showed that adsorption capacity of peanut shell and the extract was poor and stability of them was not good enough.

Novel combined method of biosorption and chemical precipitation for recovery of Pb from wastewater.

A novel combined biosorption-precipitation process has been designed and applied to recycle Pb from low concentration lead containing wastewater. Pb was firstly removed selectively from wastewater by pyromellitic dianhydride (PMDA) modified sugarcane bagasse (SB) fixed-bed column, and then, it was desorbed into the concentrated eluate and recycled by adding chemical precipitant. Adsorption performance of the column and optimum desorption and precipitation condition for Pb were investigated in detail.

Selective adsorption and recycle of Cu from aqueous solution by modified sugarcane bagasse under dynamic condition.

Tetraethylenepentamine modified sugarcane bagasse was prepared and applied to test its feasibility in removing and recovering Cu from wastewater under dynamic condition. Results showed that the Cu could be selectively absorbed from wastewater by the modified SCB fixed bed column. To understand the adsorption mechanism, Cd had been selected as the model interfering ion to investigate how co-ions influence the adsorption of Cu on the sorbent.

Simultaneous removal of cationic and anionic dyes by the mixed sorbent of magnetic and non-magnetic modified sugarcane bagasse.

Magnetic carboxyl groups modified (MMS) and non-magnetic amine groups modified (AMS) sugarcane bagasse were prepared and mixed to remove cationic and anionic dye simultaneously from aqueous solution. For comparison, the adsorption performances of MMS, AMS and the mixed sorbent for basic magenta (cationic dye) and congo red (anionic dye) were investigated in the binary system. Zeta potential analysis showed that MMS was negatively charged and AMS was positively charged in the investigated pH range.

A simple method to prepare magnetic modified beer yeast and its application for cationic dye adsorption.

The purpose of this research is to use a simple method to prepare magnetic modified biomass with good adsorption performances for cationic ions. The magnetic modified biomass was prepared by two steps: (1) preparation of pyromellitic dianhydride (PMDA) modified biomass in N, N-dimethylacetamide solution and (2) preparation of magnetic PMDA modified biomass by a situ co-precipitation method under the assistance of ultrasound irradiation in ammonia water. The adsorption potential of the as-prepared magnetic modified biomass was analyzed by using cationic dyes: methylene blue and basic magenta as model dyes.

A situ co-precipitation method to prepare magnetic PMDA modified sugarcane bagasse and its application for competitive adsorption of methylene blue and basic magenta.

Magnetic pyromellitic dianhydride (PMDA) modified sugarcane bagasse (SCB) was prepared by a situ co-precipitation method. Results showed that the magnetic modified SCB could be recycled easily by an applied magnetic field. Adsorption capacities of the magnetic sorbent for cationic dyes: methylene blue and basic magenta were 315.

Desorption behavior of methylene blue on pyromellitic dianhydride modified biosorbent by a novel eluent: acid TiO2 hydrosol.

In this study, waste beer yeast powder was modified by pyromellitic dianhydride to improve its adsorption capacities for cationic dye: methylene blue (MB). According to the Langmuir equation, the maximum uptake capacities (q(m)) of the modified biomass for MB was 830.8 mg g(-1), which was about five times than that obtained on the unmodified biomass.

Polymer modified biomass of baker's yeast for enhancement adsorption of methylene blue, rhodamine B and basic magenta.

In this study, poly (methacrylic acid) modified biomass was prepared to improve the adsorption capacities for three dyes: methylene blue (MB), rhodamine B (RB) and basic magenta (BM). FTIR and potentiometric titration demonstrated that a large number of carboxyl groups were introduced on the biomass surface, and the concentration of the functional group was calculated to be 1.4 mmol g(-1) by using the first and second derivative method.

Poly(amic acid)-modified biomass of baker's yeast for enhancement adsorption of methylene blue and basic magenta.

In this study, poly(amic acid)-modified biomass was prepared to improve the adsorption capacities for two cationic dyes, methylene blue and basic magenta. X-ray photoelectron spectroscopy and potentiometric titration demonstrated that a large number of imide, amine, and carboxyl groups were introduced on the biomass surface, and the concentrations of these functional groups were calculated to be 0.27, 1.