Spectroscopic insights into the binding characteristics of heavy metals to dissolved organic matter in landfill leachate.

Landfill leachate is produced in the process of sanitary landfilling, which contains significant amounts of dissolved organic matter (DOM) and heavy metal contaminants. Insights into the interactions between heavy metals and DOM in landfill leachate are beneficial for the understanding of heavy metal fates and optimization of landfill leachate treatment. In this work, the coherent structural changes of landfill leachate DOM during binding with various heavy metals were explored through the integration of molecular spectroscopic methods with chemometrics and statistic correlation analyses. The results indicate that protein substances, phenolic and discrete carboxyl groups in landfill leachate DOM were involved in the complexation with heavy metals, resulting in the formation of conjugated macromolecules/aggregates with high aromaticity and molecular weight/size. The fluorescent protein-like, fulvic acid-like, and humic-like fractions in DOM were engaged in the interaction, which were closely related to phenolic-like and carboxylic-like structure. Compared to membrane concentrates DOM, raw leachate DOM exhibited a higher binding affinity to heavy metals (especially for Cu2+, whilst the weakest was Cd2+). The integrated approach provides useful information in elucidating the binding processes of metals with landfill leachate DOM, including site heterogeneity, binding strength and functional group sequences.

Clean and efficient synthesis of LiFePO4 cathode material using titanium white waste and calcium dihydrogen phosphate.

Large amounts of titanium white waste are generated in the production of titanium dioxide using sulphate method, which in turn can be used to prepare LiFePO4 cathode material, thereby reducing environmental risks and achieving resource recovery. However, a key challenge lies in the elimination of impurities. In this work, a cost-efficient and straightforward approach based on phase transformation during hydrothermal treatment was proposed to utilize titanium white waste with calcium dihydrogen phosphate for the preparation of LiFePO4 cathode material. The content of Fe in the leachate was enriched to 81.5 g/L after purification, while 99.9 % of Ti and 98.36 % of Al and were successfully removed. In the subsequent process for Fe/P mother liquor preparation, the losses of Fe and P were only 5.82 % and 2.81 %, respectively. The Fe and P contents of the synthesized FePO4 product were 29.47 % and 17.08 %, respectively, and the Fe/P molar ratio was 0.986. Crystal phase of the product matched well with standard iron phosphate, and the lamellar microstructure of FePO4 was uniform with the particle size ranging from 3 to 5 µm. Moreover, the contents of impurities in the product were far below the standard. The initial discharge of LiFePO4 synthesized by the iron phosphate was 160.6 mAh.g-1 at 0.1C and maintained good reversible capacity after 100 cycles. This work may provide new strategy for preparing LiFePO4 cathode material from industrial solid waste.

Recovery of iron and aluminum from iron-rich bauxite residue by an integrated phase reconstruction approach.

The comprehensive recovery of iron and aluminum from iron-rich bauxite residue (IRBR) is of critical importance both in terms of resource utilization and environment protection, which, however, is challenging due to the intertwined phases between Iron and aluminum. In this study, an integrated phase reconstruction approach, consisting of alkali roasting, two-stage column leaching, and carbonation decomposition, was proposed for Fe/Al recovery from IRBR. The results demonstrated that aluminum and sodium were fused into soluble substances such as sodium aluminate (Na7Al3O8, NaAlO2, and Na2O (Al2O3)11) in the alkali roasting process, allowing for the separation of Al and Fe in the subsequent leaching process. Following water/FeCl3 solution leaching, the removal efficiency of aluminum reached 84.66%, and Fe content in the residue could be enriched to 55.56%. Fe can be recycled as iron concentrate, and Al in the leaching solution with 75.95 g/L can be recovered in the form of Al(OH)3 through carbonation decomposition. This work provides an alternative strategy for the recovery of resources from IRBR, with potential implications for the sustainable development of the aluminum industry.

Phosphonation of Alginate-Polyethyleneimine Beads for the Enhanced Removal of Cs(I) and Sr(II) from Aqueous Solutions.

Although Cs(I) and Sr(II) are not strategic and hazardous metal ions, their recovery from aqueous solutions is of great concern for the nuclear industry. The objective of this work consists of designing a new sorbent for the simultaneous recovery of these metals with selectivity against other metals. The strategy is based on the functionalization of algal/polyethyleneimine hydrogel beads by phosphonation. The materials are characterized by textural, thermo-degradation, FTIR, elemental, titration, and SEM-EDX analyses to confirm the chemical modification. To evaluate the validity of this modification, the sorption of Cs(I) and Sr(II) is compared with pristine support under different operating conditions: the pH effect, kinetics, and isotherms are investigated in mono-component and binary solutions, before investigating the selectivity (against competitor metals) and the possibility to reuse the sorbent. The functionalized sorbent shows a preference for Sr(II), enhanced sorption capacities, a higher stability at recycling, and greater selectivity against alkali, alkaline-earth, and heavy metal ions. Finally, the sorption properties are compared for Cs(I) and Sr(II) removal in a complex solution (seawater sample). The combination of these results confirms the superiority of phosphonated sorbent over pristine support with promising performances to be further evaluated with effluents containing radionuclides.

Coordination-driven Cu-based Fenton-like process for humic acid treatment in wastewater.

Fenton oxidation process is effective in organic pollutant degradation during wastewater treatment, but subject to narrow pH range and secondary pollution. In this work, an application-promising alternative, i.e., coordination-driven Cu-based Fenton-like process, was proposed for wastewater treatment using humic-acid (HA) as the target contaminant. The results showed that the removal of HA through Cu-based Fenton-like process can reach 70% under the condition of pH 8.0, 146.8 mmol/L H2O2, 146.8 µmol/L Cu (II), 50 °C, and 4 h. Addition of Cl- could significantly accelerate the reaction process through coordination with copper ions, while HCO3- and P2O74- exhibited opposite effects. Increasing temperature is also beneficial for advancing the reaction, and the removal of HA followed pseudo-first-order kinetics. Fluorescence spectroscopic analyses showed that the removal of HA experienced a two-stage process, i.e., oxidation followed by degradation, which is dependent of the presence of coordination ions. Parallel factor analysis was used to characterize the change of fluorescence components. Three fluorescent components, i.e., terrestrial humic-like, UV/visible terrestrial humic-like and protein-like component were identified, all of which were effectively removed. This study deepens our understanding on Cu-based Fenton-like process, and may provide a promising technology for refractory wastewater treatment.

Aluminum separation by sulfuric acid leaching-solvent extraction from Al-bearing LiFePO4/C powder for recycling of Fe/P.

Recovery of battery-grade FePO4 from Al-bearing spent LiFePO4 batteries (LFPs) is important for both prevention of environmental pollution and recycling of resources for LFPs industries. The premise for FePO4 recovery from spent LFPs is the separation of Al, because Al readily co-precipitates with FePO4 and lowers the electrochemical performance of the regenerated LiFePO4. In this work, an efficient approach involving sulfuric acid leaching followed by solvent extraction was developed to separate Al from spent LiFePO4/C powder. Di-(2-ethylhexyl) phosphoric acid (D2EHPA) in sulfonated kerosene was used as the extractant. The results showed that 96.4% of aluminum was extracted while the loss of iron was only 1.1% under the optimal conditions. The mass fraction of Al in the iron phosphate obtained from the extraction raffinate was only 0.007%, meeting the standard for preparing battery-grade FePO4. The extracted Al can be easily stripped by diluted H2SO4 solution and the extractants can be reused. Additionally, slope analysis method, FTIR spectroscopy, and ESI-MS analysis revealed that the extraction of Al in D2EHPA can be ascribed to the ion exchange between hydrogen ion of -PO(OH) and Al3+. This work may provide an economically feasible method for the recycling of valuable components from spent Al-bearing LiFePO4/C powder.

Preparation of Battery-Grade FePO4·2H2O Using the Stripping Solution Generated from Resource Recycling of Bauxite Residue.

A novel process for the high-value-use of iron from bauxite residue was proposed in this work. The process was trying to use the iron-containing stripping solution generated during resource recycling of bauxite residue to produce battery-grade FePO4·2H2O product. Thermodynamics calculation indicates that Fe and P in the stripping solution mainly existed in the form of FeHPO4+, and the theoretical pH for the conversion reaction from FePO4·2H2O to Fe(OH)3 was 1.72. The optimal condition for the synthesis of FePO4·2H2O using the stripping solution was determined as: reaction pH of 0.8, reaction temperature of 90°C, Fe/P ratio of 1, and reaction time of 24 h. XRD result showed that the synthesized FePO4·2H2O was well-crystallized and perfectly matched with the characteristic peaks of FePO4·2H2O. Moreover, all the parameters of the synthesized iron phosphate meet the quality requirements of battery precursor.

Characterization and treatment of landfill leachate: A review.

Landfill leachate is a complicated organic wastewater generated in the sanitary landfilling process. Landfill leachate must be appropriately disposed to avoid ecotoxicity and environmental damage. An in depth understanding of the physiochemical characteristics and environmental behaviors of landfill leachate is essential for its effective treatment. In this study, recent advances on the properties of landfill leachate, its characterization methods and treatment techniques are critically reviewed. Specifically, the up-to-date spectroscopic techniques for landfill leachate characterization and advanced oxidation treatment techniques are highlighted. Moreover, the drawbacks and challenges of current techniques for landfill leachate characterization and treatment are discussed, along with the future perspectives in the development of characterization and treatment approaches for landfill leachate.

Separation and recovery of arsenic from As, Cu, and Zn rich leaching liquor using a reduction-crystallization approach.

As, Cu, and Zn rich leaching liquor is generated in the leaching process of copper dust, which contains various metals with high recovery value. Herein, an approach for the direct separation and recovery of arsenic from As, Cu, and Zn rich leaching liquor was proposed. The approach includes two steps, namely SO2 reduction and arsenic crystallization. The factors affecting the reduction of As(v) to As(iii) were investigated, including the pH, SO2 dosage, and reduction temperature. In the crystallization stage, the impacts of sulfuric acid consumption and temperature on the crystallization of arsenic (As2O3) were studied. The results show that the optimal H+ concentration, temperature, and SO2 input for the arsenic reduction were 3.95 mol L-1, 45 °C, and 1.14 L g-1 As(v), respectively. While the optimal temperature and sulfuric acid dosage in As recovery process were 5 °C and 0.1 L L-1 leaching liquor, respectively. Under these conditions, the As2O3 recovery percentage reached 96.53%, and the losses of Cu and Zn were only 3.12% and 0.75%, respectively. The precipitate contained 96.72% of As2O3, 0.83% of Cu, and 0.13% Zn. Compared with the traditional technologies, this new method can improve the recovery efficiency of As2O3 and reduce the loss percentage of other valuable metals (Cu and Zn).

Degradation characteristics of dissolved organic matter in nanofiltration concentrated landfill leachate during electrocatalytic oxidation.

Nanofiltration concentrated landfill leachate (NCLL) is produced during the integration process of biodegradation and nanofiltration, containing a large amount of recalcitrant dissolved organic matter (DOM). In this work, electrocatalytic oxidation technology was employed to degrade DOM in NCLL and spectroscopic technology was applied to explore the structural changes. The results showed that under the optimal experimental condition (pH = 2.0, NaCl concentration = 0.7%, Fe2(SO4)3 concentration = 0.8%, the retention time = 6 h), the removal rates of COD, TOC, and UV254 were 99.0%, 57.4%, 99.3% respectively. Ultraviolet-Visible (UV-Vis) spectral analysis showed that aromatic CC can be effectively degraded by electrocatalytic oxidation, resulting in decreases of aromaticity and molecular weight in NCLL. Two fluorescent components (terrestrial humic-like substances and fulvic-like substances) were identified in NCLL by parallel factor analysis, which can be effectively removed by electrocatalytic oxidation with removal rates of 99.9% and 90.5%, respectively. In addition, through two-dimensional correlation spectroscopic analysis, the sequence of structural changes of the DOM in NCLL was confirmed: unsaturated double bonds → fulvic-like components/aromatic structures → terrestrial humic-like components. These spectral characterization techniques can provide a deep understanding of the degradation pathways of DOM and provide new insights for the treatment of NCLL.

Spectroscopic response of soil organic matter in mining area to Pb/Cd heavy metal interaction: A mirror of coherent structural variation.

Understanding the interaction between heavy metals and soil organic matter (SOM) in mining area is important for the clarification of the environmental behaviors of heavy metals. In this work, the coherence of structural changes of SOM during interaction with Pb2+ and Cd2+ ions were examined by using UV-vis/fluorescence spectroscopy coupled with correlation analyses. The result showed that phenolic- and carboxylic-like groups of SOM were engaged in the complexation of heavy metals (Pb2+ and Cd2+) with SOM, resulting in the formation of highly conjugated macromolecules/aggregates and an increase in molecular weight/size. Fluorescent humic-like, fulvic-like, and protein-like species were involved in the binding with Pb2+/Cd2+ ions, which were closely correlated with phenolic-like and carboxylic-like constitutes. SOM was more favorable to bind with Pb2+ ions than Cd2+ ions, with a less susceptive of SOM structure to Pb2+/Cd2+ ions in the mining area compared to those off the mining area under heavy metal stress. These results may provide a new insight for the treatment and remediation of heavy metal-polluted soil in mining area.

Arsenic removal from highly-acidic wastewater with high arsenic content by copper-chloride synergistic reduction.

A synergistic combination of chloride and copper powder was proposed as a new method to reductively remove arsenic from highly-acidic wastewater with high arsenic content (HAWA). As(III) was reduced to As(0) by copper powder in the presence of chloride and were effectively removed from HAWA. The procedure to remove arsenic was optimized as follows: initial H+ concentration of 5 mol L-1, Cu-to-As molar ratio of 8, Cl-to-As molar ratio of 10, a reaction temperature of 60 °C, copper powder particle size of 68-24 µm, and a stirring speed of 300 r min-1. Under these optimal conditions, the removal rate of arsenic was close to 100%. Kinetics results suggested that the arsenic removal process was controlled by both diffusion and chemical reactions with an apparent activation energy of 29.78 kJ mol-1. The XRD results showed that the removed arsenic in the residue existed primarily in the form of AsCu3 alloy.

Elucidating the structural variation of membrane concentrated landfill leachate during Fenton oxidation process using spectroscopic analyses.

Membrane concentrated landfill leachate (MCLL) contains large amounts of recalcitrant organic matter that cause potential hazards to the environment. Knowledge on the compositional variation of MCLL during treatment is important for a better understanding on the degradation pathway of organic pollutants. In this work, the structural change of MCLL during Fenton oxidation process was examined using spectroscopic techniques. The removal rates of COD, TOC and UV254 reached 78.9 ±â€¯1.3%, 70.2 ±â€¯1.4% and 90.64 ±â€¯1.6%, respectively, under the optimal condition (i.e., dosage of H2O2 = 9.0 mL/200 mL, H2O2/Fe(II) molar ratio = 3.0, pH = 3.0, time = 40 min). Spectral analyses suggested that aromatic/CC structure and CO bonds in MCLL can be successfully destroyed by Fenton oxidation, resulting in a decrease in molecular weight. One fulvic-like and one humic-like components were identified in MCLL, both of which can be removed by Fenton treatment. In addition, two-dimensional correlation spectroscopic analyses suggested the oxidative changes of MCLL structure in the order of fulvic-like component/unsaturated conjugated bond > aromatic structure > humic-like component. The results may provide a new insight to the understanding on the structure variation of MCLL during treatment, which is beneficial for the design of cost-effective treatment strategies.

Synergistic effect of TiO2-CuWO4 on the photocatalytic degradation of atrazine.

In this work, CuWO4 is prepared and its effect of improving photocatalytic degradation of atrazine by TiO2 as well as the synergetic mechanism is studied. Results show that the addition of CuWO4 (50 mg/L) into the reaction system can significantly enhance the efficiency of atrazine degradation, resulting in an increased degradation efficiency of 92.1% after 270 min, which is 1.94 times higher than that of the single TiO2. As the sintering temperate of CuWO4 was increased, the degradation efficiency of atrazine increased initially and then deceased after reaching a maximum at 500 °C. The origin of the synergistic effect of TiO2-CuWO4 is attributed to the introduction of solid CuWO4. The photochemical test results indicate that the photogenerated electrons transfer from irradiated TiO2 to CuWO4, which is beneficial to the O2 reduction and H2O2 formation in aqueous solution thus promoting the photocatalytic activity of TiO2. These observations unveil the importance of improving photocatalytic activity of TiO2 with Cu-bearing semiconductors.

Removal of ammonia-nitrogen in wastewater using a novel poly ligand exchanger-Zn(II)-loaded chelating resin.

In this study, a novel poly ligand exchanger-Zn(II)-loaded resin was designed to effectively remove ammonia-nitrogen (NH3-N) from wastewater. The surface morphology and structure of the Zn-loaded resin were characterized using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FTIR), respectively. SEM shows the surfaces of the Zn(II)-loaded resin were rough and nonporous and EDS demonstrated that Zn2+ was loaded onto the resin successfully. In addition, the combination form of Zn(II) with NH3-N adsorption reagent was revealed by FTIR spectra; the complex could be R-N-R-O-Zn-O-R-N-R and R-N-R-(O-Zn)2. The kinetics and equilibrium of the NH3-N adsorption onto the Zn(II)-loaded resin has been investigated. The effects of pH, reaction time, and temperature on NH3-N removal from wastewater by Zn(II)-loaded resin were investigated, and the results showed that the maximum adsorption capacity reached 38.55 mg/g at pH 9.54 at 298 K in 240 min. The adsorption ability of the modified resin decreased with an increase in temperature. Moreover, the NH3-N adsorption followed a pseudo-second-order kinetic process. The kinetic data demonstrated that the adsorption process might be limited by a variety of mechanisms. The study can provide the scientific foundation for the extensive application of a novel poly ligand exchanger-Zn(II)-loaded resin to remove NH3-N from wastewater.

Granular tri-metal oxide adsorbent for fluoride uptake: Adsorption kinetic and equilibrium studies.

A novel adsorbent embedding Mg-Al-Zr mixed oxides with millimetre-sized calcium alginate beads (SA-CMAZ) was synthesized, characterized, and applied for the secondary removal of fluoride from wastewater. Key factors affecting the fluoride adsorption, including initial fluoride concentration, contact time, initial pH and coexisting anions, were investigated. The results showed that fluoride could be removed by SA-CMAZ over a wide pH range, from 4 to 10. The presence of coexisting anions weakened the adsorption of fluoride, and the decreasing order of the removal towards fluoride was PO43->CO32->SO42->NO3-. The adsorption follows a pseudo second order kinetic with theoretical adsorption capacity (Qe,cal) and experimental adsorption capacity (Qe,exp) close to each other at the temperatures of 303K, 308K, and 313K. The equilibrium data could be fitted by the Freundlich isotherm model as the SA-CMAZ is a heterogeneous. The value of the thermodynamic parameter indicated an endothermic adsorption process. A negative value shows the feasibility and spontaneity of the material-anion interaction.

Effect of competing ions and causticization on the ammonia adsorption by a novel poly ligand exchanger (PLE) ammonia adsorption reagent.

In this paper, a poly ligand exchanger, Cu(II)-loaded chelating resin named ammonia adsorption reagent (AMAR), bearing the functional group of weak iminodiacetate acid, was prepared to efficiently remove ammonia from solutions. Batch adsorption equilibrium experiments were conducted under a range of conditions. The effects of pH on the removal of ammonia by AMAR were investigated at 25 °C. The copper loaded on the resin forms a complex with NH3 in solution under alkaline condition. The effect of alkaline dosage (AD) on the ammonia adsorption was investigated. The maximum breakthrough bed volumes were obtained when the AD was set as 0.75 mmol OH-/mL. The higher AD did not guarantee the better ammonia removal efficiency due to the forming of Cu(OH)2 precipitate between OH- in solutions and Cu(II) on the resin. The effect of competing ions on the adsorption breakthrough curve of virgin AMAR and causticized AMAR was also investigated. The results demonstrated that the existence of competing ions had a negative impact on the adsorption capacity for both virgin AMAR and causticized AMAR. After causticization, the AMAR was more resistant to the competing ions comparing with virgin AMAR. The bivalent Ca2+ affects the ammonia adsorption more than does the monovalent Na+.

A novel poly ligand exchanger - Cu(II)-loaded chelating resin for the removal of ammonia-nitrogen in aqueous solutions.

In this paper, a poly ligand exchanger, Cu(II)-loaded chelating resin bearing the functional group of weak iminodiacetate acid was prepared to efficiently remove ammonia from solutions. Batch adsorption equilibrium experiments were conducted under a range of conditions to determine the optimum adsorption conditions. The effects of contact time, pH, resin dosage and temperature on the removal of ammonia by a Cu(II)-loaded resin were determined. The maximum removal efficiency was reached at pH 9.5 at room temperature, 25°C, in 300 min. The maximum ammonia adsorption capacity was found to be 45.66 mg/L. The maximum adsorption capacities decreased with the increasing of solution temperature. Langmuir, Freundlich and Temkin isotherm models were used for fitting the adsorption experimental data without competing ions and the Langmuir isotherm model was proved to be the best-fitting model by comparing the corresponding correlation coefficients (R2) of the listed models. The effect of competing ions Na+ and Ca2+ on the adsorption of the Cu(II)-loaded resin for ammonia was investigated. The results showed that the existing of competing ions had a negative effect on the ammonia removal. The adsorption capacities decreased with the increasing concentration of competing ions. The Langmuir isotherm model was used to fit the experimental data and proved efficient. The existing of competing ions in solutions was unfavorable for ammonia adsorption and the weakening effect of bivalent Ca2+ was stronger than the monovalent Na+. The ammonia adsorption capacity was relatively high compared with other ammonia adsorbents and the Cu(II)-loaded resin was an economically feasible and promising technology for ammonia removal.

[Preparation of Mg-Al-Me(Me=La, Ce, Zr) Composite Oxides for Efficient Fluoride Uptake].

The Mg-Al-Me(Me=La, Ce, Zr) composites were prepared by co-precipitation method of Mg, Al, Me(Me=La, Ce, Zr) salt solutions with a molar ratio of 20:1:4. The sample were calcined at 500℃ for 5h as the adsorbents for removal of fluoride. The adsorbents were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The patterns of SEM indicated that three calcined sorbents were somewhat agglomerated particles to form a sheet structure after adsorption. The patterns of XRD showed that the three adsorbents fored a metal composite oxide. The effects of adsorption time, initial concentration of fluorine and coexisting ions (Cl-, NO3-, SO42-, CO32-, HCO3-, PO43-) fluorine adsorption properties on three adsorbents were tested by batch adsorption experiments. The results showed that the kinetics of fluorine on three adsorbents were well fitted by pseudo-second-order model. And the adsorption rate of fluoride on three adsorbents decreased in the order of Mg-Al-Zr > Mg-Al-La > Mg-Al-Ce. Regression results of adsorption rate controlling step test by moving boundary model indicated that intra-particle diffusion rate was not the only rate-limiting step in the adsorption of fluoride on the three materials. The equilibrium isotherm showed that the adsorption capacity of fluoride uptake by three adsorbents decreased in the order of Mg-Al-La > Mg-Al-Ce > Mg-Al-Zr. The adsorption isotherm of three adsorbents was very well described by the Langmuir models, and their linear correlations were 0.9958, 0.9790, 0.9975, respectively. The maximum adsorption capacities of fluoride on Mg-Al-La, Mg-Al-Ce, Mg-Al-Zr calculated by Langmuir model were as high as 54.22, 51.65, 50.89 mg·g-1, respectively. The results showed that the co-existing anions such as CO32-, HCO3-, PO43- had an inhibitory effect on the Mg-Al-La, Mg-Al-Ce, Mg-Al-Zr adsorption of fluoride. The effect of coexisting anions on fluoride adsorption increased in the order of Cl- < NO3- < SO42- < CO32-≈HCO3-

Recovery of gallic acid from gallic acid processing wastewater.

In this paper, an extraction technology has been investigated to recover gallic acid (GA) from GA processing wastewater. The effects of phase ratio and pH on the extraction behaviour of tributyl phosphate (TBP)/kerosene were investigated using TBP as the extractant and kerosene as the diluent. Our results showed that using 30% TBP, equilibrium was reached in 1 min. Extraction yields could be improved by increasing the phase ratio (organic phase:aqueous phase). The optimum pH values for the extraction and stripping processes were 3 and 6-9, respectively. The different GA concentrations had no noticeable effects on the distribution ratio between the organic phase and the aqueous phase during the extraction and stripping processes. The extraction yield that resulted from using the six-stage concentrating extraction was greater than 93%, with a phase ratio of 1:1 and an initial pH of 0.6. The GA concentration in the four-stage stripping liquor was greater than 100 g L(-1). Overall, the results indicated that the recovery of GA from GA processing wastewater is feasible using the methods described in this paper.