With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environmen...With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.展开更多
Water pollution caused by highly toxic Cd(II), Pb(II), and Cr(VI) is a serious problem. In the present work,a green and low-cost adsorbent of g-C_3N_4 nanosheets was developed with superior capacity for both cationic ...Water pollution caused by highly toxic Cd(II), Pb(II), and Cr(VI) is a serious problem. In the present work,a green and low-cost adsorbent of g-C_3N_4 nanosheets was developed with superior capacity for both cationic and anionic heavy metals. The adsorbent was easily fabricated through one-step calcination of guanidine hydrochloride with thickness less than 1.6 nm and specific surface area of 111.2 m^2·g^(-1). Kinetic and isotherm studies suggest that the adsorption is an endothermic chemisorption process, occurring on the energetically heterogeneous surface based on a hybrid mechanism of multilayer and monolayer adsorption. The tri-s-triazine units and surface N-containing groups of g-C_3N_4 nanosheets are proposed to be responsible for the adsorption process.Further study on pH demonstrates that electrostatic interaction plays an important role. The maximum adsorption capacity of Cd(II), Pb(II), and Cr(VI) on g-C_3N_4 nanosheets is 123.205 mg·g^(-1), 136.571 mg·g^(-1),and 684.451 mg·g^(-1), respectively. The better adsorption performance of the adsorbent than that of the recently reported nanomaterials and low-cost adsorbents proves its great application potential in the removal of heavy metal contaminants from wastewater. The present paper developed a promising adsorbent which will certainly find applications in wastewater treatment and also provides guiding significance in designing adsorption processes.展开更多
Water pollution caused by ammonia nitrogen is of major concern in many parts of the world due to the danger it poses to the environment and human health.This study focuses on the development of an inexpensive and envi...Water pollution caused by ammonia nitrogen is of major concern in many parts of the world due to the danger it poses to the environment and human health.This study focuses on the development of an inexpensive and environmental adsorbent by means of modified corncob.The objective of this paper was to investigate the adsorption behavior of NH^+_4-N from wastewater by modified corncob.Corncob was modified with KMn O_4.The physico-chemical properties of modified corncob were characterized by fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM).It was found that the adsorption capacity of corncob was improved significantly after modification with KMn O_4.The p H significantly affected the adsorption efficiency of modified corncob to NH^+_4-N.The best p H value of corncob adsorbing NH^+_4-N was 7.The coexistence of Na^+had a significant effect on the adsorption of NH^+_4-N.The adsorption process of modified corncob to NH^+_4-N followed the pseudo-first order kinetic model.Langmuir model could well simulate the adsorption behavior of NH^+_4-N on modified corncob.The maximum adsorption capacity of NH^+_4-N on modified corncob can reach 4.85 mg/g.The adsorption process of NH^+_4-N was monolayer adsorption.Moreover,modified corncob adsorbed NH^+_4-N was fertilizer conservation especially for nitrogen.The utilization of modified corncob with NH^+_4-N adsorption in the farmland could promote the gradual release of nutrients,thus providing nutrients for plant growth.It was proposed that if combined with biological method,the amount of removed NH^+_4-N from wastewater could be increased significantly.展开更多
Effects of wastewater discharge on the coastal area in Gaza strip Palestine are not fully investigated. This study investigated the effect wastewater discharge of the physical and chemical properties of marine water i...Effects of wastewater discharge on the coastal area in Gaza strip Palestine are not fully investigated. This study investigated the effect wastewater discharge of the physical and chemical properties of marine water in the coastal area over a period of 2 year. Sea water and sediment samples were collected from about 20 different sites. The water and the sediments were collected wastewater/sea water mixing zone at depth 0, 2.5 and 5 m water column depth at a direct wastewater discharging pipe line from different location and similarly from other locations. Water temperature T, electric conductivity (EC), dissolved oxygen (DO), pH, total dissolved solid (TDS) and salinity were determined for water samples using field equipment such as pH-meter, DO meter, TDS-/ and EC-meter. On the other hand, NO<sub>3</sub><sup>-</sup>, SO<sub>4</sub><sup>2-</sup>, PO<sub>4</sub><sup>3-</sup> were determined in the laboratory using chemical methods, details are described in materials and method section. Results showed average and standard deviation of T, EC, DO, pH, TDS and salinity were 22.02°C ± 4.1°C, EC: 58.41 ± 4.8 ms/cm;DO: 6.96 ± 1.8 mg/L;pH: 7.69 ± 0.37;TDS: 30.51 ± 3.29 and salinity 4.39 ± 0.12 (%);whereas, average and standard deviation of NO<sub>3</sub><sup>-</sup>: were 299.8 ± 204.1 mg/L;SO<sub>4</sub><sup>2-</sup>, 5736.9 ± 817.1;and PO<sub>4</sub><sup>3-</sup>: 164.35 ± 120.7 mg/L. The measured values indicate significant differences due to high value of standard deviation of some measured parameters. This indicates the influence of wastewater discharge in sea water as shown inside the manuscript in the appropriate section. The study recommends efficient treatment of wastewater and reuses it for agricultural purposes instead of discharging it in sea.展开更多
基金supported by the National Natural Science Foundation of China (No.52364022)the Natural Science Foundation of Guangxi Province,China (Nos.2023JJA160192 and 2021GXNSFAA220096)+1 种基金the Guangxi Science and Technology Major Project,China (No.AA23073018)the Guangxi Chongzuo Science and Technology Plan,China (No.2023ZY00503).
文摘With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.
基金Supported by the National Natural Science Foundation of China(21525625)the National Basic Research Program(973 Program) of China(2014CB745100)+3 种基金the(863) High Technology Project of China(2013AA020302)the Chinese Universities Scientific Fund(JD1417)China Postdoctoral Science Foundation funded project(2017M610038)the Fundamental Research Funds for the Central Universities(ZY1712,XK1701)
文摘Water pollution caused by highly toxic Cd(II), Pb(II), and Cr(VI) is a serious problem. In the present work,a green and low-cost adsorbent of g-C_3N_4 nanosheets was developed with superior capacity for both cationic and anionic heavy metals. The adsorbent was easily fabricated through one-step calcination of guanidine hydrochloride with thickness less than 1.6 nm and specific surface area of 111.2 m^2·g^(-1). Kinetic and isotherm studies suggest that the adsorption is an endothermic chemisorption process, occurring on the energetically heterogeneous surface based on a hybrid mechanism of multilayer and monolayer adsorption. The tri-s-triazine units and surface N-containing groups of g-C_3N_4 nanosheets are proposed to be responsible for the adsorption process.Further study on pH demonstrates that electrostatic interaction plays an important role. The maximum adsorption capacity of Cd(II), Pb(II), and Cr(VI) on g-C_3N_4 nanosheets is 123.205 mg·g^(-1), 136.571 mg·g^(-1),and 684.451 mg·g^(-1), respectively. The better adsorption performance of the adsorbent than that of the recently reported nanomaterials and low-cost adsorbents proves its great application potential in the removal of heavy metal contaminants from wastewater. The present paper developed a promising adsorbent which will certainly find applications in wastewater treatment and also provides guiding significance in designing adsorption processes.
文摘Water pollution caused by ammonia nitrogen is of major concern in many parts of the world due to the danger it poses to the environment and human health.This study focuses on the development of an inexpensive and environmental adsorbent by means of modified corncob.The objective of this paper was to investigate the adsorption behavior of NH^+_4-N from wastewater by modified corncob.Corncob was modified with KMn O_4.The physico-chemical properties of modified corncob were characterized by fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM).It was found that the adsorption capacity of corncob was improved significantly after modification with KMn O_4.The p H significantly affected the adsorption efficiency of modified corncob to NH^+_4-N.The best p H value of corncob adsorbing NH^+_4-N was 7.The coexistence of Na^+had a significant effect on the adsorption of NH^+_4-N.The adsorption process of modified corncob to NH^+_4-N followed the pseudo-first order kinetic model.Langmuir model could well simulate the adsorption behavior of NH^+_4-N on modified corncob.The maximum adsorption capacity of NH^+_4-N on modified corncob can reach 4.85 mg/g.The adsorption process of NH^+_4-N was monolayer adsorption.Moreover,modified corncob adsorbed NH^+_4-N was fertilizer conservation especially for nitrogen.The utilization of modified corncob with NH^+_4-N adsorption in the farmland could promote the gradual release of nutrients,thus providing nutrients for plant growth.It was proposed that if combined with biological method,the amount of removed NH^+_4-N from wastewater could be increased significantly.
文摘Effects of wastewater discharge on the coastal area in Gaza strip Palestine are not fully investigated. This study investigated the effect wastewater discharge of the physical and chemical properties of marine water in the coastal area over a period of 2 year. Sea water and sediment samples were collected from about 20 different sites. The water and the sediments were collected wastewater/sea water mixing zone at depth 0, 2.5 and 5 m water column depth at a direct wastewater discharging pipe line from different location and similarly from other locations. Water temperature T, electric conductivity (EC), dissolved oxygen (DO), pH, total dissolved solid (TDS) and salinity were determined for water samples using field equipment such as pH-meter, DO meter, TDS-/ and EC-meter. On the other hand, NO<sub>3</sub><sup>-</sup>, SO<sub>4</sub><sup>2-</sup>, PO<sub>4</sub><sup>3-</sup> were determined in the laboratory using chemical methods, details are described in materials and method section. Results showed average and standard deviation of T, EC, DO, pH, TDS and salinity were 22.02°C ± 4.1°C, EC: 58.41 ± 4.8 ms/cm;DO: 6.96 ± 1.8 mg/L;pH: 7.69 ± 0.37;TDS: 30.51 ± 3.29 and salinity 4.39 ± 0.12 (%);whereas, average and standard deviation of NO<sub>3</sub><sup>-</sup>: were 299.8 ± 204.1 mg/L;SO<sub>4</sub><sup>2-</sup>, 5736.9 ± 817.1;and PO<sub>4</sub><sup>3-</sup>: 164.35 ± 120.7 mg/L. The measured values indicate significant differences due to high value of standard deviation of some measured parameters. This indicates the influence of wastewater discharge in sea water as shown inside the manuscript in the appropriate section. The study recommends efficient treatment of wastewater and reuses it for agricultural purposes instead of discharging it in sea.
