Synthesis,Crystal Structure and Water Vapor Adsorption Property of a New Supramolecular Architecture

A new complex, [Cu（HL）（phen）（H2O）]·4H2O（1, H3L·HCl = 5-（（4-carboxypiperidin-1-yl）methyl）isophthalic acid hydrochloride, phen = 1,10-phenanthroline）, has been hydrothermally prepared and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and PXRD. Complex 1 crystallizes in monoclinic, space group P21/c with a = 14.5520（14）, b = 12.6659（12）, c = 15.5006（14） A, β = 97.224（2）o, V = 2834.3（5） A3, Z = 4, C27H33N3O11 Cu, Mr = 639.10, Dc = 1.498 g/cm3, μ = 0.837 mm-1, S = 1.047, F（000） = 1332, the final R = 0.0423 and w R = 0.1118 for 18772 observed reflections（I 〉 2σ（I））. The compound is a Cu（Ⅱ） centre mononuclear molecule in the asymmetric unit. The independent binuclear [Cu2（HL）2（phen）2] units are bridged to form a three-dimensional（3D） supramolecular polymer by extensive hydrogen bonds and π-π non-covalent bonding interactions. Moreover, thermogravimetric（TG） analysis and gas adsorption property of 1 were also discussed.

Adsorption of Cu(Ⅱ) from Aqueous Solution Using Activated Carbon Modified with Nitric Acid

The objective of the presented work was to assess the adsorption processes of Cu(Ⅱ) from aqueous solution onto a granular activated carbon (GAC) and a modified activated carbon (MAC) with nitric acid. Available surface functional groups, pH of the isoelectric point (pHIEP), and Fourier transform infrared spectroscopes were obtained to characterize the GAC/MAC. Factors influencing Cu(Ⅱ) adsorption such as adsorbent dosage, pH of solution, and contact time of the adsorption onto the MAC/GAC had been investigated in a batch experiment. Experimental equilibrium data had been obtained and modelled using both Freundlich and Langmuir classical adsorption isotherms and the data fitted better to Langmuir isotherm. It was found that nitric acid modification increased the Cu(Ⅱ) adsorption capacity to 90.9 mg/g, which was higher than the unmodified carbon by 41%. Two simplified models including pseudo-first-order and pseudo-second-order equations were selected to follow the adsorption processes.

The Application of Polytetrafluoroethylene (PTFE) Fiber Grafted Acrylic Acid as a Cation Exchanger for Removing Cu^(12)

The polytetrafluoroethylene fiber grafted acrylic acid was used as a cation exchanger. The exchange capacity of the cation fiber is 3.06 mmol/g. The maximum Cu2+ adsorption capacity is 107.48 mg/g. It could be desorbed completely by 1mol/L HCl.

Mechanism of Cu(Ⅱ) adsorption inhibition on biochar by its aging process

Biochar exposed in the environment may experience a series of surface changes, which is called biochar aging. In order to study the effects of biochar aging on Cu（Ⅱ） adsorption, we analyzed the surface properties before and after biochar aging with scanning electron microscopy（SEM） coupled to an energy-dispersive X-ray spectrometer（EDX） and diffuse reflectance infrared Fourier transform spectroscopy（DRIFTS）, and then explored the influence of the aging process on Cu（Ⅱ） adsorption by batch experiments. After the aging process, the oxygen concentration, phenolic hydroxyl groups, aromatic ethers and other oxygen-containing functional groups on the biochar surface increased, while carboxyl groups slightly decreased. Thus, over a range of pH, the cation exchange capacity（CEC） and adsorption capacity of Cu（Ⅱ） on the aged biochar were smaller than those of new biochar,indicating that when biochar is incubated at constant temperature and water holding capacity in the dark, the aging process may inhibit Cu（Ⅱ） adsorption. Meanwhile, the dissociation characteristics of oxygen-containing functional groups changed through the aging process, which may be the mechanism by which the biochar aging process inhibits the Cu（Ⅱ） adsorption. Carboxyl groups became more easily dissociated at low pH（3.3–5.0）,and the variation of maximum adsorption capability（qm） of Cu（Ⅱ） on the old biochar was enlarged. Phenolic hydroxyl groups increased after the aging, making them and carboxyl groups more difficult to dissociate at high pH（5.0–6.8）, and the variation of qmof Cu（Ⅱ） on the aged biochar was reduced.

Effect and mechanism of changes in physical structure and chemical composition of new biochar on Cu(Ⅱ)adsorption in an aqueous solution

To improve the adsorption effect of biochar on heavy metal Cu(II),we prepared new biochar and explored its modification process influence on original biochar’s physical structure and chemical composition as well as its adsorption mechanism for Cu(II)in an aqueous solution.Through research work,we have reached some significant conclusions:(1)The modified biochar(M2-800)can adsorb Cu(II)at the rate of 98.039 mg g–1,38.8 times higher than that of the original biochar C800(2.525 mg g–1);(2)The biochar modification process boosts its etching and pore expansion,helping Cu(II)enter the inner surface of the adsorbent,but chemical adsorption is still the most essential fixation method for Cu(II);(3)The alkaline modification process promotes the formation of oxygen-containing functional groups,in which–OH/–COOH and iron ions would form C-O-Fe structures such as hydroxyl bridges(Fe-O–)and carboxy bridges(Fe-OOC–);(4)Carboxyl is the primary site of Cu(II)fixation in M2-800,and M2-800 has higher electronegativity(–47.8 mV)and larger pH(11.61),so that Cu(II)can be removed by electrostatic attraction and precipitation.

Optimization of polyacrylonitrile-cysteine resin synthesis and its selective removal of Cu(Ⅱ) in aqueous solutions

Polyacrylonitrile beads（PAN） cysteine（CS） was synthesized from polyacrylonitrile beads（PAN） and cysteine（CS）.The content of the functional group and the percentage conversion of the functional group of PAN-CS prepared under the optimum condition using response surface methodology（RSM） for the first attempt were 3.22 mmol/g and 35.78%.The structure was characterized by ET-IR and elemental analysis.The adsorption properties of the resin for Cu（Ⅱ） were investigated by batch and column experiments.Batch adsorption results suggested that PAN-CS had higher adsorption capability for Cu（Ⅱ）than other metal ions and maximum saturated adsorption capacity was 184.7 mg/g.The resin and its metal complexes were studied by FT-IR.Furthermore,the resin can be eluted easily using 1 mol/L HC1.PAN-CS can provide a potential application for selective removal of copper from waste solution.

Preparation and application of a novel orotic acid chelating resin for removal of Cu(Ⅱ) in aqueous solutions

A novel chelating resin OABA,capable of removing Cu（Ⅱ） from aqueous solution,was synthesized via the reaction of macroporous chloromethylated PS-DVB copolymer beads with orotic acid.The elemental analysis（EA）,Fourier transform infrared spectroscopy（FT-IR）,and scanning electron microscopy microscope-energy dispersive X-ray spectroscopy（SEM-EDS） were used in the characterization of the synthesized chelating resin.Multiple,static batch adsorption experiments were conducted at different initial concentrations and temperatures.OABA showed good adsorption capacity for Cu（Ⅱ） and the equilibrium data could be well matched with the Freundlich isotherm model.Coexisting sodium chloride and calcium chloride in solutions favored the Cu（Ⅱ） adsorption.Moreover,the desorption process of Cu（Ⅱ） was tested and over 90%regeneration efficiency for the spent OABA was achieved at ammonia concentrations ranging from 1.0%to 2.0%.The results suggested that OABA would be a potential alternative adsorbent for Cu（Ⅱ）,even with other heavy metal ion treatments of wastewater.