Applied Water Science (v.8, #4)

The presence of lignin and its derivatives in pulp effluent increases the pollution load on the environment. With an aim of better degradation and decolourization of wastewater, this study proposes the utilization of different ligninolytic enzymes from novel bacterial strains. Four novel bacterial strains of Klebsiella pneumoniae (K. pneumoniae strains NITW715076, NITW715076_1, NITW715076_2 and NITW715076_3) were isolated and identified. The ligninolytic enzymes were characterized by plate assay method. For the optimization of various process parameters of effluent sample, different approaches were used like one factor at a time and statistical optimization through response surface methodology (RSM). Further to validate the above data, enzyme activity, total phenolic concentration, GC–MS analysis and seed germination test were also performed. The ligninolytic enzymes produced were characterized as laccase and Manganese peroxidase (MnP). In lignin degradation and decolourization studies, consortia 1 (K. pneumoniae NITW715076_2 + K. pneumoniae NITW715076_1) (82.31%) was found more effective when compared to axenic culture (K. pneumoniae NITW715076_2) (74.1%). In RSM studies, Laccase and MnP activities were increased by 20% and 18%, respectively, as compared to one factor at a time optimization method. In addition, the enzyme activity for laccase and MnP after prediction by RSM was found 53338 IU/L and 147900 IU/L, respectively. The R 2 values for both the enzymes were found to be significant. Further, GC–MS analysis also showed the degradation of different organic pollutants in effluent. Lastly, the seed germination test using consortia 1 corroborated the evidence of detoxification of industrial effluent. Effluent treated by consortia 1 showed better results in degradation and decolourization of lignin and their derivatives. Therefore, consortia 1 can be used for various industrial purposes like fruit juice clarification, diagnostic purposes and enhanced bioethanol production.
Keywords: Wastewater; Laccase; Manganese peroxidase; Response surface methodology; GC–MS; Decolourization

This study investigated wastewater management using Vetiveria zizanioides planted in vertical flow constructed wetland (VFCW). Wastewater from the grit removal chamber and the primary sedimentation tank of Daspoort Wastewater Treatment Works was fed into six-pilot VFCW consisting of 1000-L plastic tanks having 500-mm-deep, 10–15-mm-diameter granite substrate planted with V. zizanioides. Irrigation of macrophytes using effluent from the grit removal chamber and primary sedimentation tanks was done after 3 months of planting and the VFCW monitored. Wastewater samples were collected and analysed using standard procedures. The pollution parameters of the initial sample were total alkalinity 297 ± 27.3 mg/L; COD 627 ± 149.0 mg/L; EC 82.53 ± 5.4 ms/m; free and saline ammonia 36.02 ± 4.1 mg/L, nitrate/nitrite 0.09 ± 0.1 mg/L; pH 7.66 ± 0.4; phosphate 3.07 ± 0.3 mg/L, sulphate 44.57 ± 3.1 mg/L; TDS 551 ± 37.8; TSS 319 ± 34.2 mg/L; and TKN 41 ± 6 mg/L. Percentage removal of 89.57, 98.34% TSS; 98.95, 98.62 free and saline ammonia; 89.87, 91.44% TKN; and 80.65, 58.02% COD for screen and settled wastewater, respectively, was obtained from the VFCW. VFCW using locally available V. zizanioides is a viable alternative for municipal wastewater treatment.
Keywords: Vertical flow constructed wetland; Vetiveria zizanioides ; Municipal wastewater

The future of date palm cultivation in the Lower Jordan Valley of the West Bank by B. G. J. S. Sonneveld; A. Marei; M. D. Merbis; A. Alfarra (1-12).
High water consumption and specific soil requirements warrant a long-term planning for date palm cultivation. Hence, this study presents a detailed procedure to calculate water and land balances that assess the suitability for date palm cultivation in three districts of the West Bank. It applies crop response functions to relate spatially explicit land suitability and salinity levels to net revenues. Furthermore, it compares net present values and benefit–cost ratios under various discount rates and salinity levels to assess economic feasibility. Date palm cultivation in Jericho-Al Ghoor is economically achievable, but additional land amendments are required for expansion in Nablus and Tubas districts. Prevailing average salinity levels have minor negative influence on future date palm developments.
Keywords: Date palm; Irrigation; West Bank; Salinity; Cost benefit analysis

Hydrogeological environment of an area includes surface and subsurface water resources. Groundwater is continuously getting recharged by surface water sources and rainfall. Recharge and discharge of an area can be reflected by water-table rise and drawdown. Water table of an area represents the groundwater strategy in the formation and majorly depends on the amount of precipitation. An attempt is carried out to analyze the correlation between rainfall and water table in arid climatic condition within the Gulbarga watershed, Karnataka, India. Rainfall and water-table data were collected from Department of Mines and Geology, Government of Karnataka, which consists of information from 2001 to 2011. Month-wise data are processed into distinctive four seasonal data, namely winter, summer, monsoon and post-monsoon. The rainfall data are analyzed, and accordingly they have been classified as good year and bad year depending upon the amount of precipitation. The study focuses on the need of rainwater harvesting and artificial recharge structures to improve groundwater resource sustainability for future generation.
Keywords: Rainfall analysis; Good/bad year; Water-table analysis; Correlation

The adsorption properties of activated carbon were successfully tested toward the elimination of hazardous HCrO4 (30, 50, 70 and 100 mg L−1). The material was prepared from Algerian date pits by physical and chemical activations of ZnCl2/CO2 in the goal to develop the microporous volume. The characterization by N2 adsorption at 77 K, the mercury intrusion porosimetry and scanning electron microscopy showed important textural properties. CO2 increases the specific surface area (1192 m2 g−1) and pore volume (0.96 cm3 g). The HCrO4 adsorption is described by a pseudo-first-order kinetic model, and the equilibrium data are fitted by the Langmuir model with a maximal adsorption capacity of 46.72 mg/g within 30 min and a constant K L (0.12 L g−1). The remaining HCrO4 concentrations (8, 23, 32.5 and 43.5 mg L−1) were photocatalytically reduced on the hetero-system ZnCo2O4/TiO2 down to 5 mg L−1. The spinel ZnCo2O4, prepared by co-precipitation from the nitrates precursors and characterized by photoelectrochemistry, gives a conduction band of − 1.49 V SCE, more cathodic than the HCrO4 level (0.53 V). Therefore, the photoelectrons transfer toward HCrO4 species is achieved through TiO2 located midway between the spinel and chromate levels. The photocatalysis is investigated by varying the catalyst dose and HCrO4 concentration. ZnCo2O4 has a gap of 1.82 eV and the best reduction efficiency (82%) was obtained under visible light (50 mW cm−2) and optimal conditions (HCrO4 23 mg L−1, pH ~ 7, ZnCo2O4/TiO2 50/50%) and follows a first-order kinetic with a rate constant of 3.86 × 10−3 min−1.
Keywords: Date pits; Chemical and physical activation; Adsorption; Chromate; Photoreduction; Hetero-system ZnCo2O4/TiO2

In the current study, an effort was made to assess the geochemistry of groundwater by random collection of the samples from 15 different borewells located in various parts of Varanasi City, Uttar Pradesh, India. Geology of the study region is dominated by Quaternary alluvial sediments of Pleistocene to recent times where the younger alluvium receives fresh deposits of silt, clay and loam from periodic flood events. Ca–Mg–HCO3was inferred as major hydrogeochemical facies from Piper trilinear diagram. Ca–Mg type and HCO3 type were the dominating cation and anion facies, respectively. Hydrogeochemistry reveals that the cation abundance follows the order Na+> Mg2+ > Ca2+ > K+ and anion abundance HCO3  > Cl > NO3  > SO4 2− > F. As per Gibb’s plot, chemical weathering of rock minerals is affecting the quality of groundwater. Overall, most of the samples for majority of parameters lie within the allowable limits as set by WHO (guideline for drinking water quality, fourth edn, WHO, Geneva, p 340, 2004) except nitrate, which varied in the range of 40.32–78.97 mg/l. 80% of the groundwater samples in which nitrate exceeded beyond acceptable limit (50 mg/l), as per WHO standard, which may be due to poor sewerage, human excreta leakage from septic tanks, poorly maintained disposal of solid waste locally, agricultural activities, wastewater irrigation and irrigation runoff. The Water quality index (WQI) value of the study region depicts that 93% samples lie in the category of excellent water and 7% in good water category. Good positive correlation of NO3–Cl (r = 0.60) and Na–NO3 (r = 0.55) signifies an anthropogenic input of these ions into the subsurface water of the study region. The various indices such as electrical conductivity (EC), salinity, percent sodium, sodium absorption ratio (SAR), residual sodium carbonate (RSC), permeability index (PI), Kelly’s ratio and magnesium ratio are used to check the fitness of ground water for irrigation uses which shows that groundwater samples of the study region is good to permissible for agricultural uses.
Keywords: Groundwater; TDS; Nitrate; Water quality index; Residual sodium carbonate (RSC)

Agricultural waste of bagasse was employed for investigating its lead (Pb2+) removal potential from wastewater of battery manufacturing industry. To optimize maximum removal efficacy of the bagasse, it was thermally modified in the form of biochar. Adsorption kinetics and mechanism including various parameters (contact time, dose and pH) were studied employing biochar prepared from bagasse waste. The optimum adsorption occurred at pH 5 with 140 min. of contact time utilizing 5 g of adsorbent dosage at room temperature (25 ± 3 °C). The maximum removal efficiency was recorded as 12.741 mg g−1 with 75.376% of removal at optimum pH 5 as compared to the initial concentration in the effluent. The result illustrated the most suitable fit was for Langmuir isotherm with monolayer and homogenous adsorption of Pb2+. The kinetics involved in the process was observed to be pseudo-second-order, which indicates chemisorption as a major phenomenon involved in the process. The characterization of the adsorbent biochar was done by SEM, EDX and FTIR analysis that provided details about ultrastructural and functionality of organic moiety present to have porous and rough surface, favoring the adsorption process. The functional groups identified by the FTIR analysis demonstrated involvement of carboxyl groups in Pb2+ binding. Postadsorption elution of metal-loaded bagasse was executed by 0.1 M HNO3 with about 90% of regeneration.
Keywords: Biosorption; Biochar; Isotherms; Kinetics; Desorption; Water pollution; Heavy metals

Nowadays, the adverse effect of drilling operation performances on the environment is considered as one of the major concern of petroleum industries which should be taken into the consideration to virtually eliminate the unnecessary expenses of improving the wasting quality before entering to the environment. Volume and toxicity of discharged materials evaluate surface discharge severity. The ubiquitous utilization of formate fluids has revolutionized the way petroleum industries have conquered the lower drilling inefficiencies. We investigated the profound impact of different pollutants on the potassium/sodium formate fluids using experimental tests. The particular sample for mud pollution test was formate fluid with starch biopolymers. To do this, five samples of formate fluids were made, and each of them was polluted by several pollutants such as cement, lime, acid, alkali and stucco. Consequently, rheological properties and the pH changes and their effect on the formate fluids were evaluated.
Keywords: Formate fluids; Rheological properties; Pollutants; Core samples

Hydrogeochemical characteristics and spatial distribution of groundwater quality in Arusha well fields, Northern Tanzania by Nyamboge Chacha; Karoli N. Njau; George V. Lugomela; Alfred N. N. Muzuka (1-23).
Arusha aquifers have been exploited intensively serving as the main source of domestic water supply in the city. But the quality of groundwater is not clearly documented for future planning and management. Hydrogeochemical assessment was carried out to establish groundwater quality and its spatial distribution with the aid of geostatistical techniques. Groundwater samples were collected and analyzed for major cations and anions using conventional methods of water analysis. Well lithology and geological map were considered for hydrogeological interpretation of the area. The results of piper diagram revealed Na–K–HCO3 water type with sodium and bicarbonate ions dominating in all samples. High fluoride concentrations and general groundwater chemistry are mainly controlled by aquifer lithology than anthropogenic activities. The levels of anthropogenic pollution indicators such as nitrate, chloride and sulfate in deep wells are generally low and most likely coming from natural sources. The geological sections indicate two potential aquifers (volcanic sediment and weathered/fractured formation) both yield water containing significant concentration of fluoride. Fluoride concentrations were higher than WHO guidelines (1.5 mg/l) and Tanzanian standards (4.0 mg/l) by 82 and 36% of the analyzed groundwater samples, respectively. The southern part of the study area yields groundwater of better quality for human consumption than northern zones which is at high elevation on the foot of Mt. Meru. With exception of fluoride, the quality of groundwater in the study area is generally suitable for drinking purpose and other socioeconomic uses.
Keywords: Groundwater quality; Hydrogeochemical; Arusha

Even though collaborative governance has become an important model to address river problems, the practice of collaboration among different sectors to govern river problems is weak in Addis Ababa city. Therefore, this study was intended to investigate the problem of weak cross-sectoral collaboration for the governance of river problems in Addis Ababa City. Employing qualitative research approach, the study relied on both primary and secondary data sources. Accordingly, interview and observation were conducted to gather relevant data. Secondary data were collected from different quarterly reports, river assessments and researches. The study found out that cross-sectoral collaboration is characterized by the lack of involvement of various non-governmental sectors, the problem of legitimacy, and the representation of sectors by individuals who have no expertise or experience on river issues. On the other hand, the challenges are the exclusion of river from the agendas of each sector, lack of commitment of authorities to share information and resources, and the absence of sectors in the implementation of river plans in different river sites in terms of giving trainings, supervising, and evaluating river sites. Establishing committee at all levels, including river in the annual plans of each sector, and appointing river experts in different sectors are identified as important mechanisms of dealing with collaboration problems. These problems of weak cross-sectoral collaborative governance of rivers had resulted in the deteriorating quality of rivers, environmental hazards to the vegetation of agricultural crops, and health and related impacts on biotic elements of the ecosystem.
Keywords: Collaborative governance; Cross-sectoral collaboration; River governance

A new and simple method for the determination of trace amounts of brilliant green was developed by coacervative extraction and spectrophotometry. The method is based on the extraction of brilliant green with coacervates made up of sodium dodecyl sulfate as an anionic surfactant, in the presence of saturated NaCl solution. The effect of various experimental parameters such as pH of solutions, concentration of surfactant and concentration of salt was investigated using central composite design based on response surface methodology. Under the optimum conditions the calibration graph was linear in the range of 0.03–2.2 µg mL−1 with a detection limit of 0.012 µg mL−1. The relative standard deviation for seven replicates of 1.2 µg mL−1 brilliant green was 1.75%. The proposed method was successfully applied for the determination of brilliant green in different real samples including fish farming water, river water and tap water samples.
Keywords: Coacervative extraction; Spectrophotometry; Brilliant green; SDS; Experimental design

The present work suggests a simple approach for simulating the dispersion of pollutants in rivers and streams with the aid of computational fluid dynamics technique. The two-dimensional advection–dispersion equation was solved using FlexPDE code to predict the biochemical oxygen demand (BOD) and the total dissolved solids (TDS) concentrations at the confluence of Diyala with Tigris Rivers. In this model, two sets of data were used for calibration and validation processes. Various values of longitudinal and transverse dispersion coefficients were adopted in the model to determine the suitable value using the trial-and-error method. The results revealed that the best agreement between simulated and measured values was observed when the longitudinal and transverse dispersion coefficients are close to 10 and 5 m2/s, respectively. The results showed that the proposed methodology is more suitable for TDS, while for BOD, it needs an accurate representation of the chemical or biological transformations.
Keywords: Pollutant transport; Diyala River; Tigris River; Water quality; FlexPDE

We studied the distribution of proto- and metazooplankton coupled with environmental factors in the coast area around Kneiss Islands (Central Mediterranean Sea). Zooplanktonic communities were sampled during summer 2009 and summer 2010 at three stations. Our results showed difference in suspended matter concentrations between summer 2009 (92.88 ± 7.15 mg L−1) and summer 2010 (47.37 ± 23.12 mg L−1). Large variations in the N/P ratio were recorded (6.94–36.76) due to the direct influence of the variability in concentration of both the dissolved inorganic nitrogen and dissolved inorganic phosphate components of the ratio. Ciliates abundance peaked in summer 2009 and was 3 times more abundant than summer 2010. Ciliates community composition was dominated by loricate ciliates (75% of total ciliates) in summer 2009 and naked ciliates (56% of total ciliates) in summer 2010. Copepods were the most abundant metazooplankton present during the entire study period, comprising 30–96% of the total metazooplankton community. Small planktonic copepods reached important abundance, particularly oithonids, were found to largely dominate copepods community in both summer 2009 (Oithona nana, 45% of total copepods) and summer 2010 (Oithona similis, 22% of total copepods). The small planktonic species Paracalanus parvus (54% of total copepods) was abundant during summer 2010. The results also indicate that (1) ciliates abundance was very low, showing a possible predation by copepods and also by heterotrophic dinoflagellates, (2) copepods capable to complete a top-down control on phytoplankton and ciliates, with preference to ciliates more than diatoms of similar size and shape and (3) the resistance of loricate ciliates compared to naked ciliates may be explained by their capacity to escape grazing due to the existence of a protective lorica.
Keywords: Kneiss Islands; Nutrients; Ciliates; Zooplankton

Unaffordable construction cost of conventional water treatment plant and distribution system in most developing countries makes difficult to provide safe and adequate water for all households, especially for the rural setup. Water treatment at the source can be the best alternative. Solar disinfection is one alternative among point of use treatments. In this study, aqua lens, photovoltaic box and glass bottle were used subsequent to plant coagulants to evaluate microbial reduction potentials. Laboratory- and field-based experiments were conducted from May to August 2016. The Escherichia coli, total coliforms and heterotrophic plate counts were used as indicator organisms. The result indicated that aqua lens (AL), photovoltaic box (PV) and glass bottle (GB) have high inactivation rate subsequently almost for all indicator organisms in short solar exposure time. Total coliforms were inactivated in AL (SD = 15.8 °C, R 2 = 0.92) followed by PV inactivation temperature association (SD = 11.6 C, R 2 = 0.90), and the GB concentrator was inactivated (SD = 10.9 °C, R 2 = 0.70) at turbidity level of 3.41 NTU. As the study indicated, aqua lens coupled with Moringa oleifera coagulant can be an effective with minimum cost for household water treatment system. The study also concludes heterotrophic bacteria were more resistant than other types of bacteria in SODIS with similar exposure time.
Keywords: Acrylic glass; Aqua lens; Moringa oleifera ; Photovoltaic box; Solar disinfection; Water treatment

Groundwater recharge estimation studies in a khondalitic terrain of India by Yellapu Siva Prasad; Bekkam Venkateswara Rao (1-9).
Agriculture is the main occupation in the Kandivalasa river sub-basin (KRSB) covered with khondalitic terrain of Eastern Ghats of India. The farmers are mainly depending on groundwater for irrigation in non-monsoon period in the study area; as such it is important to know how much rainfall recharge is occurring to the groundwater table. The groundwater recharge is assessed in the KRSB by collecting the pre- and post-monsoon groundwater levels at 42 observation wells and rainfall data covering the entire basin during the years 2013–2016. The groundwater recharge has been calculated using both water table fluctuation method and rainfall infiltration method. The study revealed in the basin that the per cent of rainfall converting to the groundwater recharge is 11.12, 13.18, 9.51 and 12.80% for the years 2013, 2014, 2015 and 2016, respectively. The study has also revealed that the heavy rainfall events with prolonged time lead to the rise in the groundwater levels, thereby increasing the groundwater recharge. It is also observed that the deeper the pre-monsoon groundwater level, the more the recharge in the basin.
Keywords: Khondalites; Groundwater recharge; Pre-monsoon groundwater levels; Kandivalasa river sub-basin

In this study, adsorption potential of soya bean adsorbent for lead (Pb) and arsenic (As) has been assessed in order to consider its suitability for purification of wastewater containing heavy metals. The main focus of study was on Pb and As. Batch experiments were performed to study the adsorption of Pb and As on soya bean absorbent. The effect of various experimental parameters (adsorbent dose, contact time, temperature and pH) was studied, and optimal conditions were determined. The effect of adsorbent dose on the biosorption of Pb and As from aqueous solution was studied at 37 °C by varying the adsorbent amount from 1 g/100 ml to 4 g/100 ml. Highest amount of Pb and As was adsorbed at sorbent amount of 3 g/100 ml. The optimum pH for removal of As and Pb was found to be 2.0 and 4.0 ± 0.26. Maximum biosorption of Pb and As was achieved at 37 °C. The maximum percentage removal of Pb and As was attained at 60 min of shaking time. Langmuir and Freundlich isotherm models were utilized for equilibrium studies. It was found that biosorption by soya bean adsorbent was exothermic in nature. The thermal degradation analysis suggested that the degradation occurs in two steps and adsorbent is thermally stable.
Keywords: Biosorption; Soya bean adsorbent; Lead and arsenic; Sorption isotherm and thermal analysis of biosorbent

Design, operation and management of water resource projects are influenced by the amount of discharge passing through the stream. Discharge at the gauging site is generally estimated by developing single-valued simple rating curves. However, in case of unsteady flows, hysteresis affect is introduced in the stage discharge relationship and as such single-valued rating curves are no longer valid for such situations. The present paper presents a simple spreadsheet-based optimization approach for modelling the hysteresis-affected discharge rating curves. Generalized reduced gradient (GRG) technique has been reported as a reliable tool for handling optimization problems; therefore, in the present paper, it has been applied to estimate discharge for two sites with hysteresis affect based on Jones formula. Comparison of results shows that discharge estimated by GRG technique is as efficient as genetic algorithm and the goodness-of-fit criteria shows that the rating curves obtained by using Jones formula fit the observed data better than single-valued simple rating curves for both the sites considered in the present study. Application of spreadsheet-based GRG optimization technique could prove very helpful to the hydrometric offices.
Keywords: GRG; Hysteresis; Optimization; Rating curves; Spreadsheet

Globally the average annual loss of reservoir capacity is approximately 1%. Pakistan is confronting major issue of sedimentation which is continuously depleting the useful storage of reservoirs. GSTARS3 model was used to determine the rate of deposition and sediment pattern of Chashma Reservoir since its operation. The model was calibrated and validated for bathymetric survey of 2008 and 2012. The results of GSTARS3 were incorporated to a GIS software to visualize sediment accumulation in reservoir. The study reveals that sediment flushing of the Chashma Reservoir can be carried out during flood season at a pond level of 638.15 ft. (194.51 m). However, its negative impact if any on the hydropower generation needs to be analysed. Accordingly, modified operation rules would be required.
Keywords: Sedimentation; Bathymetric survey; GSTARS3; Sediment accumulation; Flushing; Operational rules

The study of groundwater quality parameters is most essential for irrigation and drinking water, and its quality is a serious problem around the study area. The spatial analysis of groundwater quality mapping is required and stimulated us to undertake a systematic work of groundwater quality parameters for suitable water exploration of crops and drinking purposes from bore wells and open wells in basaltic hard rock area. A detailed study of physico-chemical parameters composition of groundwater was performed from groundwater quality data of post-monsoon (December) in the year of 2013. The groundwater quality data were collected from 35 wells samples randomly distributed in area. GIS is a powerful tool for representation and analysis of spatial information related to groundwater resources management. To achieve this aim, the groundwater quality samples were analysed for the preparation of groundwater quality maps such as pH, electrical conductivity, TDS, Cl and Mg. The groundwater quality parameters were analysed for all the sampling locations using IWD interpolation techniques. In this study, groundwater quality values observed are minimum and maximum values of pH (6.2–8 on scale), electrical conductivity (348–1598 S/cm), total dissolved solids (268.32–707.95 mg/l), carbonate (0–30 mg/l), bicarbonate (0.9–58.9 mg/l), chloride (1.15–28.36 mg/l), sulphate (17.4–105 mg/l), nitrate (0.4–6.0 mg/l), calcium (2.35–7.24 mg/l), magnesium (2.88–3.73 mg/l), sodium (0.57–3.31 mg/l), potassium (0.26–1.2 mg/l), sulphate (0.5–4.64 mg/l), bicarbonate+ carbonate (1.07–11.16 mg/l) and carbonate (0–0.79 mg/l) in hard rock area. The spatial variation maps were derived and integrated through ARC GIS 10.3 software. The interpolation tool was used to obtain the spatial distribution of groundwater quality parameters in the basaltic hard rock area. Therefore, the result of groundwater analysis of large number of groundwater samples has been found to be suitable for drinking and irrigation purposes in the basaltic hard rock area.
Keywords: Groundwater; Basaltic rock; GIS; Inverse distance weighted method and GPS

A newly green photocatalyst support for azo dye remediation under UV light irradiation by Hayrunnisa Nadaroglu; Asghar Lesani; Seyedeh Sara Soleimani; Aynur Babagil (1-8).
A new cellulosic material “corn silk” was modified with titanium dioxide nanoparticles as a novel photocatalyst support. In this study, the prepared support was tested for the removal of Reactive Black 5 (RB5) as an azo dye pollutant candidate from synthetic samples. High capability of decolorization (> 99%) was achieved after 30 s using the corn silk/TiO2 photo-biocatalyst. The effect of important parameters such as pH of the medium, the amount of photocatalyst, mixing rate and dye concentration was investigated and modified. UV–Vis spectroscopy, scanning electron microscopy (SEM), X-ray powder diffraction and Fourier-transform IR spectrometry were applied to characterize the effect of functionalization, structure, surface morphology and photocatalyst properties of the support and mineralization of pollutants. It was observed that the maximum decolorization of RB5 occurred at pH 3.0, 25 °C, 300 rpm, 30 s using the corn silk/TiO2 composite material for this study. The results reveal that corn silk/TiO2 composite has high and significant photocatalytic activity.
Keywords: Corn silk; Titanium (IV) oxide NPs; Textile dye; Reactive Black 5; UV photodegradation

Water shortage is among the critical challenges facing many countries located in the arid zone of the southern the Mediterranean region. In the northern Sinai, El-Salam Canal and shallow groundwater in the Quaternary aquifer are considered the main irrigation sources for reclamation of 62,000 acres situated along the Mediterranean coast. The chemistry of surface water of El-Salam Canal varies greatly from the western to the eastern sides. Additionally, the groundwater chemistry is greatly influenced by dilution due to seepage of El-Salam Canal water. The historical and recent records of water chemistry show great variation of the concentrations of dissolved Al3+, Cu2+ and Zn2+ in both surface and groundwater, based on sampling time and locality. The concentrations of these heavy metals occasionally exceed the international recommended limits for drinking and short-term irrigation standards. The removal of dissolved heavy metals from water is crucial to fill the gap between the water supply and the growing demands using possible techniques of water treatment. Consequently, zeolite nanocomposites are one of the materials that have been used for water treatment. Magnetic zeolite nanocomposites (MZNCs) were prepared by the chemical co-precipitation of Fe2+ and Fe3+ in the presence of zeolite. The prepared magnetic nanocomposites were characterized by TEM, SEM, EDX, XRD, FTIR, TGA and VSM. The results show that MZNCs have a cubic crystal structure and good thermal stability. The MZNCs were used to remove Al(III), Zn(II) and Cu(II) from simulated water and then were easily separated from the medium by external permanent magnet. Batch adsorption experiments were conducted, and the effects of pH, initial ion concentration, adsorbent dose and contact time were studied. The selected pH range (pH = 5–6) and temperature (27 °C) in the batch adsorption experiments were close to the pH range of the surface and groundwater field data. Furthermore, the chosen initial concentrations and adsorbent doses were within the heavy metals concentration ranges in El-Salam Canal and the adjacent groundwater. The MZNCs show great removal capacity of heavy metals where 0.1 g is able to clean contaminated water with high concentrations (0.5–3 g/l) of Cu(II) and Zn(II) within 20 min and within 30 min for Al(III). The adsorption kinetics data of the system were well fitted to pseudo-second-order model, which indicates a faster kinetic sorption by the composites. Adsorption isotherms were studied using Langmuir and Freundlich isotherms. Although both of them fit the data, the Freundlich isotherm had the best fit for the selected metals.
Keywords: El-Salam Canal water; Hydrogeochemistry; Water treatment; Magnetic zeolite; Nanocomposite

Synthesis of ZnO nanostructure using activated carbon for photocatalytic degradation of methyl orange from aqueous solutions by Mahda Sadat Nasrollahzadeh; Mojtaba Hadavifar; Seyedeh Sima Ghasemi; Mansour Arab Chamjangali (1-12).
In this research, zinc oxide (ZnO) nanostructure was prepared by using zinc acetate (as precursor) and carboxylic derivative of activated carbon (as matrix). Activated carbon was modified by oxidation with nitric acid to get carboxylic derivative (AC–COOH). Then, zinc was loaded on the surface of modified activated carbon by an impregnation method. The ZnO nanostructure was characterized by BET, XRD and SEM that confirmed achieving of ZnO nanoparticles with a size of 21–31 nm and surface area of 17.78 m2 gr−1. The efficiency of the catalyst was evaluated in the photocatalytic decomposition of aqueous solution of azo dye methyl orange (MO). Major parameters such as pH, dose of catalyst, stirring effect, initial concentration of dye and solution oxygen effect were considered. Activity measurements under UV radiation showed acceptable results for the photodegradation of MO. The efficiency of catalyst prepared with non-modified activated carbon for the photodegradation of MO was also evaluated. The results confirmed that ZnO prepared using carboxylic derivative of activated carbon as matrix had better photocatalytic activity than ZnO prepared by non-modified carbon matrix.
Keywords: Zinc oxide; Activated carbon; Photodegradation; Methyl orange

The indiscriminate consumption of antibiotics and their introduction into the environment have caused global concerns. Typically, following consumption, these compounds are introduced into the environment after incomplete metabolism, and a large portion of them are impossible to remove using conventional wastewater treatment systems. The main aim of this study was to determine the feasibility of using a TiO2/UV-C nanophotocatalyst doped with trivalent iron for the removal of amoxicillin from aquatic solutions. The nanophotocatalyst was prepared and characterized by SEM, XRD, EDX, DRS, and photoluminescence spectrum. The influences of different parameters, including nanocatalyst concentration (30–90 mg/L), initial concentration of amoxicillin (10–45 mg/L), and pH (3–11) at different time intervals (30–120 min) on antibiotic removal efficiency were investigated. Antibiotic concentration was measured with an HPLC device. All experiments were replicated three times according to the Standard Methods for the Examination of Water and Wastewater, 20th edition. Data were analyzed using SPSS 19 and the ANOVA statistical test. Optimal conditions for removing amoxicillin from a synthetic solution were as follows: pH 11, initial concentration of antibiotic = 10 mg/L, nanocatalyst = 90 mg/L, and contact time = 120 min. The optimal conditions were also used to remove amoxicillin from Dana Pharmaceutical Company wastewater. The removal efficiencies of antibiotic for synthetic and pharmaceutical wastewater were 99.14 and 88.92%, respectively. According to the results, the nanophotocatalyst TiO2/UV-C may be used for the removal of significant amounts of amoxicillin from pharmaceutical wastewater.
Keywords: Antibiotic; Amoxicillin; Titanium dioxide doped by Fe3+ ; Removal; Nano-photocatalyst; UV radiation